WHITE PAPER laptop computers and other consumer devices as well as in SSDs because it offers a valuable The high memory density of today’s TLC NAND Flash devices means that a storage device such as are supported by Silicon Motion controllers than by those of any other company. Configuring NAND Flash cells for optimized operation combination of high memory density and high performance. This means that huge data storage Silicon Motion’s FerriSSD® can provide up to 480GB of data capacity in a surface-mount BGA package The controller embedded in Silicon Motion AEC-Q100 qualified storage devices also provides the capacity can be provided in a small packaged device, and the user benefits from rapid access to stored with a tiny footprint of just 20mm x 16mm. Silicon Motion’s understanding of the behavior of NAND Flash at high temperatures underlies the capability for the user to configure operation of TLC NAND Flash to extend data integrity. The SLCMode™ data and quick data storage operations. operation of its Ferri storage products, all of which are available in versions qualified to AEC-Q100 function available in Ferri products virtually groups together TLC or MLC cells into a one-bit SLC-like Silicon Motion’s Ferri Family But the small size of TLC cells means that they wear out at a faster rate than SLC cells, a factor which Grades 3 and 2. configuration. This is ideal for use cases in which the nominal storage capacity (in TLC mode) is These characteristics are important as well to automotive manufacturers. But automotive applications the Flash controller embedded in a storage device has to take into account. Every Program/ Erase (P/E) over-specified. Operation with the SLCMode feature turned on reduces the nominal capacity, but gives AEC-Q100 Qualified Embedded Storage impose special requirements which raise important additional questions about manufacturers’ choice cycle slightly degrades the oxide layer in the cells on which a P/E operation is performed. Smaller TLC Controller technology extends data retention SLC-like data retention and data integrity performance. of NAND storage device: cells have a thinner oxide layer than the larger SLC cells, so they degrade faster, and can on average As Figure 2 shows, the acceleration of electron leakage from NAND cells at high withstand fewer P/E cycles. As this paper describes below, proprietary NANDXtend technology solve temperatures dramatically shortens data retention, down to as little as 2 days at 85°C for an MLC cell Ferri products offer MLCmode operation as well as SLCmode, giving users the ability to choose the This qualification process is exhaustive, and has been proved to effectively screen out potentially this problem in Ferri series storage devices. which has undergone its rated maximum number of P/E cycles. ideal balance between data integrity and capacity for their application. In addition, they provide an defective parts. Components which pass the tests and achieve AEC-Q100 qualification have SSDLifeGuard™ feature which automatically monitors the health status of the SSD, and triggers the demonstrated a remarkably high level of reliability and integrity in a demanding set of environmental NAND Flash cells also experience electron The Silicon Motion solution is to monitor the voltage at every cell in an array to detect those in which controller to implement data protection and error correction operations when blocks or pages are at risk. How the latest NAND Flash-based storage devices achieve and application conditions. leakage over time. If too much charge leaks leakage has progressed to a critical state, and then to reprogram at-risk cells. The Ferri product feature high reliability in high-temperature automotive applications from a cell, its data can no longer be read which implements this technology, IntelligentScan + DataRefresh, is capable of extending NAND Flash Extending NAND cell operation beyond ten years One of the most difficult elements of AEC-Q100 qualification for NAND Flash-based storage products out. ‘Data retention’ – the length of time for array lifetimes far beyond the nominal P/E cycle lifetime specified by the Flash manufacturer (see AEC-Q100 qualification for automotive storage devices calls for zero-defect performance at high With the introduction of every new generation of passenger vehicle, the automation, safety and to achieve is to pass the high- temperature and accelerated lifetime simulation tests. Storage systems which data can be stored in a cell – declines Figure 3). The intelligence in the IntelligentScan feature also includes responding automatically to temperature – a very challenging requirement for NAND Flash-based devices, because of the navigation systems become more sophisticated. Supported by an array of cameras, radar (RF) and must maintain reliable operation at continuous temperatures of up to 85°C for AEC-Q100 qualification as more P/E cycles are performed. And heat temperature, and scanning more frequently when operating at high temperature. acceleration in data leakage from NAND cells at high temperatures of 85°C and above. The fact that LiDAR (optical) ranging systems, sensors, and other detection systems, Advanced Driver Assistance to Grade 3, and up to 105°C for Grade 2. And the compact, chip-style packages in which the latest accelerates electron leakage, so data Silicon Motion’s Ferri products are qualified for automotive use at temperatures up to 105°C is Systems (ADAS) generate and process huge quantities of digital data. Infotainment systems, too, are products, such as Silicon Motion’s Ferri family, are housed, have more constrained thermal pathways retention also declines faster as temperature When a cell’s oxide layer has degraded so much that it can no longer be sufficiently recharged, the testament to the effectiveness of the unique technologies, such as IntelligentScan + DataRefresh, growing in code size as drivers demand superior navigation and information systems, and passengers than in the larger enclosure of a typical free-standing SSD used as a computing accessory. rises, as Figure 2 shows. IntelligentScan function will repair it if possible, or retire it, thus avoiding any risk to data integrity. which Silicon Motion has developed for managing NAND Flash arrays. look for more entertainment options in the front and rear of the cabin. In vehicles, the long-term reliability and lifetime of an electronics component such as a mass storage To maintain reliable operation and data integrity in automotive storage devices, Silicon Motion applies The controller in Ferri products also implements advanced global , so that P/E operations, The optimization of storage products for automotive applications results from Silicon Motion’s In functional terms, the car is becoming a data center on wheels – and like a data center, it needs device are crucial criteria. The automotive industry applies strict qualification tests, according to the various unique technologies which draw on its long experience in NAND Flash memory control. An and thus wear, are evenly allocated across an entire array. commitment to the automotive market – a commitment which is also demonstrated by its compliance high-speed access to a large data storage capacity. Reliability concerns have led automotive AEC-Q100 standard, to the integrated circuits used in automotive Electronic Control Units (ECUs), with understanding of these technologies will help the automotive system designer to evaluate NAND So this is the problem for NAND Flash-based storage devices for automotive applications such as the with the full range of automotive industry standards, including IATF 16949, ASPICE, and VDA 6.3. manufacturers to end the use of traditional (HDD) storage devices, which offer a the aim of achieving zero defects over a long lifetime at temperatures of 85°C or higher. Flash-based storage devices with confidence that they are robust and reliable enough for use in infotainment system: in a car’s center console, an infotainment ECU might be required to operate at limited lifetime and are prone to mechanical failure. vehicles. temperatures as high as 85°C. But data loss is not acceptable in infotainment applications such as Automotive manufacturers can also take confidence from Silicon Motion’s leadership position in the The goal of reducing the component defect rate to zero is important because of the long lifetime of a mapping and navigation. And the AEC-Q100 standard mandates a defect rate of zero when tested at market for merchant SSD controllers and embedded storage devices. Silicon Motion is the leading vehicle, the high number of components in a vehicle, and the huge cost of rectifying a known fault in a NAND Flash cell operation at high temperature temperatures up to 85°C (for Grade 3 qualification). specialist manufacturer of NAND Flash controller technology, and can draw on more than 20 years’ To see how technology can counter the effect of high temperatures on NAND Flash cells, it is important Data from Cloud fleet of vehicles which are in service – not to mention the reputational damage to a car maker’s brand. experience in developing specialized processor ICs which manage NAND components. In the past ten to understand the operation of these cells. In Flash memory, data bits are represented by stored It is a problem that a Silicon Motion storage controller, and the firmware which it runs, can solve. years, Silicon Motion has shipped more than six billion NAND Flash controllers, more than any other To illustrate the point simply, imagine a single Electronic Control Unit (ECU) consisting of 1,000 parts. charge (electrons) in cells. When NAND Flash technology first came on to the market, memory arrays company in the world.

→ → → If the ECU manufacturer tolerated a defect rate as low as 1ppm, this single ECU alone would be were made of Single-Level Cell (SLC) elements. In SLC NAND, the cell stores one bit of data – a 1 or 0. Central role of storage controller Sensing Detect Analysis Reaction In-Vehicle Standard responsible for 1,000 faults in a fleet of 1 million vehicles. And according to a 2019 report form analyst A NAND Flash-based storage system consists of two basic elements: So now automotive manufacturers can embed robust solid-state storage into infotainment and ADAS • AEC-Q100 • ISO 26262 firm IHS Markit, a new luxury vehicle can contain as many as 150 ECUs1. As technology advanced, NAND Flash chip ECUs with confidence that Silicon Motion’s Ferri products’ lifetime, data integrity and data retention (((((((( • ASPICE manufacturers responded to demand for higher will meet users’ expectations for vehicle lifetimes of ten years and beyond. This is why the automotive industry imposes the goal of a zero defect rate. And its strategy for reaching memory density by developing Multi-Level Cell In-Vehicle Computing Storage Needs this goal is to apply a component qualification process, codified in the various AEC-Q10x standards. (MLC) technology, which stores two bits per cell, The basic role of the controller is the bridge between the NAND Flash cells and the host processor 1 IHS Markit report cited at: • Environmental Monitoring In-Vehicle Infotainment • Performance • Issues Analysis • Map / GPS • Data Correction The criteria for AEC-Q100 qualification, for example, are extremely strict, and verify a component’s and then Triple-Level Cell (TLC) technology, with which writes to and reads from the memory. The controller manages the mapping of bits to cell https://www.eenewsautomotive.com/news/number-automotive-ecus-continues-rise • Reaction in time • Connect to mobile • Reliability reliability across a number of test parameters. The main reliability tests are: three bits per cell (see Figure 1). This means that addresses. • NVMe SR-IOV for storage • Entertainment Application • Wide temperature range the cell volume-per-bit has declined with each new generation of NAND Flash. NAND cell size Silicon Motion has more than 20 years’ experience of developing the specialized controller ICs which Instead, automotive system designers today prefer to use a mass storage device which is based on also shrinks as semiconductor fabrication manage NAND components. Its deep understanding of NAND characteristics enables it to design both NAND Flash memory technology, such as a Solid State Disk (SSD), eMMC drive or UFS (Universal Flash processes advance from older process nodes to highly optimized ICs and related firmware controller platforms. In fact, more NAND Flash components, Storage) device. NAND Flash has become the preferred technology for mass storage in mobile phones, the latest sub-10nm nodes. including 3D Flash products from , , Micron, Samsung, SK Hynix, and YMTC,

- 1 - laptop computers and other consumer devices as well as in SSDs because it offers a valuable The high memory density of today’s TLC NAND Flash devices means that a storage device such as are supported by Silicon Motion controllers than by those of any other company. Configuring NAND Flash cells for optimized operation combination of high memory density and high performance. This means that huge data storage Silicon Motion’s FerriSSD® can provide up to 480GB of data capacity in a surface-mount BGA package The controller embedded in Silicon Motion AEC-Q100 qualified storage devices also provides the capacity can be provided in a small packaged device, and the user benefits from rapid access to stored with a tiny footprint of just 20mm x 16mm. Silicon Motion’s understanding of the behavior of NAND Flash at high temperatures underlies the capability for the user to configure operation of TLC NAND Flash to extend data integrity. The SLCMode™ data and quick data storage operations. operation of its Ferri storage products, all of which are available in versions qualified to AEC-Q100 function available in Ferri products virtually groups together TLC or MLC cells into a one-bit SLC-like But the small size of TLC cells means that they wear out at a faster rate than SLC cells, a factor which Grades 3 and 2. configuration. This is ideal for use cases in which the nominal storage capacity (in TLC mode) is These characteristics are important as well to automotive manufacturers. But automotive applications the Flash controller embedded in a storage device has to take into account. Every Program/ Erase (P/E) over-specified. Operation with the SLCMode feature turned on reduces the nominal capacity, but gives impose special requirements which raise important additional questions about manufacturers’ choice cycle slightly degrades the oxide layer in the cells on which a P/E operation is performed. Smaller TLC Controller technology extends data retention SLC-like data retention and data integrity performance. of NAND storage device: cells have a thinner oxide layer than the larger SLC cells, so they degrade faster, and can on average As Figure 2 shows, the acceleration of electron leakage from NAND Flash memory cells at high withstand fewer P/E cycles. As this paper describes below, proprietary NANDXtend technology solve temperatures dramatically shortens data retention, down to as little as 2 days at 85°C for an MLC cell Ferri products offer MLCmode operation as well as SLCmode, giving users the ability to choose the Performance – in use cases such as driver assistance and navigation, latency is a key figure This qualification process is exhaustive, and has been proved to effectively screen out potentially this problem in Ferri series storage devices. which has undergone its rated maximum number of P/E cycles. ideal balance between data integrity and capacity for their application. In addition, they provide an of merit. Automotive manufacturers require fast Read and Write speeds and high data defective parts. Components which pass the tests and achieve AEC-Q100 qualification have SSDLifeGuard™ feature which automatically monitors the health status of the SSD, and triggers the throughput. demonstrated a remarkably high level of reliability and integrity in a demanding set of environmental NAND Flash cells also experience electron The Silicon Motion solution is to monitor the voltage at every cell in an array to detect those in which controller to implement data protection and error correction operations when blocks or pages are at risk. and application conditions. leakage over time. If too much charge leaks leakage has progressed to a critical state, and then to reprogram at-risk cells. The Ferri product feature Data integrity – every Read and Write operation carries a risk of generating bit errors, which from a cell, its data can no longer be read which implements this technology, IntelligentScan + DataRefresh, is capable of extending NAND Flash Extending NAND cell operation beyond ten years can lead to data loss or corruption. Reliability is a critical factor in the automotive market, One of the most difficult elements of AEC-Q100 qualification for NAND Flash-based storage products out. ‘Data retention’ – the length of time for array lifetimes far beyond the nominal P/E cycle lifetime specified by the Flash manufacturer (see AEC-Q100 qualification for automotive storage devices calls for zero-defect performance at high With the introduction of every new generation of passenger vehicle, the automation, safety and and in a storage device, data integrity is an important marker of reliability. to achieve is to pass the high- temperature and accelerated lifetime simulation tests. Storage systems which data can be stored in a cell – declines Figure 3). The intelligence in the IntelligentScan feature also includes responding automatically to temperature – a very challenging requirement for NAND Flash-based devices, because of the navigation systems become more sophisticated. Supported by an array of cameras, radar (RF) and must maintain reliable operation at continuous temperatures of up to 85°C for AEC-Q100 qualification as more P/E cycles are performed. And heat temperature, and scanning more frequently when operating at high temperature. acceleration in data leakage from NAND cells at high temperatures of 85°C and above. The fact that LiDAR (optical) ranging systems, sensors, and other detection systems, Advanced Driver Assistance Data retention – unlike a consumer device such as a mobile phone, a vehicle is expected to to Grade 3, and up to 105°C for Grade 2. And the compact, chip-style packages in which the latest accelerates electron leakage, so data Silicon Motion’s Ferri products are qualified for automotive use at temperatures up to 105°C is Systems (ADAS) generate and process huge quantities of digital data. Infotainment systems, too, are have an operating lifetime of at least ten years. Automotive manufacturers want to be products, such as Silicon Motion’s Ferri family, are housed, have more constrained thermal pathways retention also declines faster as temperature When a cell’s oxide layer has degraded so much that it can no longer be sufficiently recharged, the testament to the effectiveness of the unique technologies, such as IntelligentScan + DataRefresh, growing in code size as drivers demand superior navigation and information systems, and passengers confident that their chosen NAND storage device will retain data for the life of the vehicle. than in the larger enclosure of a typical free-standing SSD used as a computing accessory. rises, as Figure 2 shows. IntelligentScan function will repair it if possible, or retire it, thus avoiding any risk to data integrity. which Silicon Motion has developed for managing NAND Flash arrays. look for more entertainment options in the front and rear of the cabin. In vehicles, the long-term reliability and lifetime of an electronics component such as a mass storage To maintain reliable operation and data integrity in automotive storage devices, Silicon Motion applies The controller in Ferri products also implements advanced global wear leveling, so that P/E operations, The optimization of storage products for automotive applications results from Silicon Motion’s In functional terms, the car is becoming a data center on wheels – and like a data center, it needs device are crucial criteria. The automotive industry applies strict qualification tests, according to the various unique technologies which draw on its long experience in NAND Flash memory control. An and thus wear, are evenly allocated across an entire array. commitment to the automotive market – a commitment which is also demonstrated by its compliance high-speed access to a large data storage capacity. Reliability concerns have led automotive AEC-Q100 standard, to the integrated circuits used in automotive Electronic Control Units (ECUs), with understanding of these technologies will help the automotive system designer to evaluate NAND So this is the problem for NAND Flash-based storage devices for automotive applications such as the with the full range of automotive industry standards, including IATF 16949, ASPICE, and VDA 6.3. manufacturers to end the use of traditional Hard Disk Drive (HDD) storage devices, which offer a the aim of achieving zero defects over a long lifetime at temperatures of 85°C or higher. Flash-based storage devices with confidence that they are robust and reliable enough for use in infotainment system: in a car’s center console, an infotainment ECU might be required to operate at limited lifetime and are prone to mechanical failure. vehicles. temperatures as high as 85°C. But data loss is not acceptable in infotainment applications such as Automotive manufacturers can also take confidence from Silicon Motion’s leadership position in the The goal of reducing the component defect rate to zero is important because of the long lifetime of a mapping and navigation. And the AEC-Q100 standard mandates a defect rate of zero when tested at market for merchant SSD controllers and embedded storage devices. Silicon Motion is the leading vehicle, the high number of components in a vehicle, and the huge cost of rectifying a known fault in a NAND Flash cell operation at high temperature temperatures up to 85°C (for Grade 3 qualification). specialist manufacturer of NAND Flash controller technology, and can draw on more than 20 years’ fleet of vehicles which are in service – not to mention the reputational damage to a car maker’s brand. To see how technology can counter the effect of high temperatures on NAND Flash cells, it is important experience in developing specialized processor ICs which manage NAND components. In the past ten to understand the operation of these cells. In Flash memory, data bits are represented by stored It is a problem that a Silicon Motion storage controller, and the firmware which it runs, can solve. years, Silicon Motion has shipped more than six billion NAND Flash controllers, more than any other To illustrate the point simply, imagine a single Electronic Control Unit (ECU) consisting of 1,000 parts. charge (electrons) in cells. When NAND Flash technology first came on to the market, memory arrays company in the world. If the ECU manufacturer tolerated a defect rate as low as 1ppm, this single ECU alone would be were made of Single-Level Cell (SLC) elements. In SLC NAND, the cell stores one bit of data – a 1 or 0. Central role of storage controller responsible for 1,000 faults in a fleet of 1 million vehicles. And according to a 2019 report form analyst A NAND Flash-based storage system consists of two basic elements: So now automotive manufacturers can embed robust solid-state storage into infotainment and ADAS firm IHS Markit, a new luxury vehicle can contain as many as 150 ECUs1. As technology advanced, NAND Flash chip ECUs with confidence that Silicon Motion’s Ferri products’ lifetime, data integrity and data retention manufacturers responded to demand for higher will meet users’ expectations for vehicle lifetimes of ten years and beyond. This is why the automotive industry imposes the goal of a zero defect rate. And its strategy for reaching memory density by developing Multi-Level Cell this goal is to apply a component qualification process, codified in the various AEC-Q10x standards. (MLC) technology, which stores two bits per cell, The basic role of the controller is the bridge between the NAND Flash cells and the host processor 1 IHS Markit report cited at: The criteria for AEC-Q100 qualification, for example, are extremely strict, and verify a component’s and then Triple-Level Cell (TLC) technology, with which writes to and reads from the memory. The controller manages the mapping of bits to cell https://www.eenewsautomotive.com/news/number-automotive-ecus-continues-rise reliability across a number of test parameters. The main reliability tests are: three bits per cell (see Figure 1). This means that addresses. the cell volume-per-bit has declined with each Accelerated environmental stress testing Electrical verification new generation of NAND Flash. NAND cell size Silicon Motion has more than 20 years’ experience of developing the specialized controller ICs which Instead, automotive system designers today prefer to use a mass storage device which is based on Accelerated lifetime simulation testing Defect screening also shrinks as semiconductor fabrication manage NAND components. Its deep understanding of NAND characteristics enables it to design both NAND Flash memory technology, such as a Solid State Disk (SSD), eMMC drive or UFS (Universal Flash Packaging and assembly tests Package integrity testing processes advance from older process nodes to highly optimized ICs and related firmware controller platforms. In fact, more NAND Flash components, Storage) device. NAND Flash has become the preferred technology for mass storage in mobile phones, Die fabrication testing the latest sub-10nm nodes. including 3D Flash products from Intel, Kioxia, Micron, Samsung, SK Hynix, Western Digital and YMTC,

- 2 - laptop computers and other consumer devices as well as in SSDs because it offers a valuable The high memory density of today’s TLC NAND Flash devices means that a storage device such as are supported by Silicon Motion controllers than by those of any other company. Configuring NAND Flash cells for optimized operation combination of high memory density and high performance. This means that huge data storage Accelerated environmental Die fabrication testing Silicon Motion’s FerriSSD® can provide up to 480GB of data capacity in a surface-mount BGA package The controller embedded in Silicon Motion AEC-Q100 qualified storage devices also provides the stress testing capacity can be provided in a small packaged device, and the user benefits from rapid access to stored with a tiny footprint of just 20mm x 16mm. Silicon Motion’s understanding of the behavior of NAND Flash at high temperatures underlies the capability for the user to configure operation of TLC NAND Flash to extend data integrity. The SLCMode™ Electrical verification data and quick data storage operations. Accelerated lifetime operation of its Ferri storage products, all of which are available in versions qualified to AEC-Q100 function available in Ferri products virtually groups together TLC or MLC cells into a one-bit SLC-like simulation testing But the small size of TLC cells means that they wear out at a faster rate than SLC cells, a factor which Grades 3 and 2. configuration. This is ideal for use cases in which the nominal storage capacity (in TLC mode) is Defect screening These characteristics are important as well to automotive manufacturers. But automotive applications the Flash controller embedded in a storage device has to take into account. Every Program/ Erase (P/E) over-specified. Operation with the SLCMode feature turned on reduces the nominal capacity, but gives Packaging and impose special requirements which raise important additional questions about manufacturers’ choice assembly tests Package integrity testing cycle slightly degrades the oxide layer in the cells on which a P/E operation is performed. Smaller TLC Controller technology extends data retention SLC-like data retention and data integrity performance. of NAND storage device: cells have a thinner oxide layer than the larger SLC cells, so they degrade faster, and can on average As Figure 2 shows, the acceleration of electron leakage from NAND Flash memory cells at high withstand fewer P/E cycles. As this paper describes below, proprietary NANDXtend technology solve temperatures dramatically shortens data retention, down to as little as 2 days at 85°C for an MLC cell Ferri products offer MLCmode operation as well as SLCmode, giving users the ability to choose the This qualification process is exhaustive, and has been proved to effectively screen out potentially this problem in Ferri series storage devices. which has undergone its rated maximum number of P/E cycles. ideal balance between data integrity and capacity for their application. In addition, they provide an defective parts. Components which pass the tests and achieve AEC-Q100 qualification have SSDLifeGuard™ feature which automatically monitors the health status of the SSD, and triggers the demonstrated a remarkably high level of reliability and integrity in a demanding set of environmental NAND Flash cells also experience electron The Silicon Motion solution is to monitor the voltage at every cell in an array to detect those in which controller to implement data protection and error correction operations when blocks or pages are at risk. and application conditions. leakage over time. If too much charge leaks leakage has progressed to a critical state, and then to reprogram at-risk cells. The Ferri product feature from a cell, its data can no longer be read which implements this technology, IntelligentScan + DataRefresh, is capable of extending NAND Flash Extending NAND cell operation beyond ten years One of the most difficult elements of AEC-Q100 qualification for NAND Flash-based storage products out. ‘Data retention’ – the length of time for array lifetimes far beyond the nominal P/E cycle lifetime specified by the Flash manufacturer (see AEC-Q100 qualification for automotive storage devices calls for zero-defect performance at high With the introduction of every new generation of passenger vehicle, the automation, safety and to achieve is to pass the high- temperature and accelerated lifetime simulation tests. Storage systems which data can be stored in a cell – declines Figure 3). The intelligence in the IntelligentScan feature also includes responding automatically to temperature – a very challenging requirement for NAND Flash-based devices, because of the navigation systems become more sophisticated. Supported by an array of cameras, radar (RF) and must maintain reliable operation at continuous temperatures of up to 85°C for AEC-Q100 qualification as more P/E cycles are performed. And heat temperature, and scanning more frequently when operating at high temperature. acceleration in data leakage from NAND cells at high temperatures of 85°C and above. The fact that LiDAR (optical) ranging systems, sensors, and other detection systems, Advanced Driver Assistance to Grade 3, and up to 105°C for Grade 2. And the compact, chip-style packages in which the latest accelerates electron leakage, so data Silicon Motion’s Ferri products are qualified for automotive use at temperatures up to 105°C is Systems (ADAS) generate and process huge quantities of digital data. Infotainment systems, too, are products, such as Silicon Motion’s Ferri family, are housed, have more constrained thermal pathways retention also declines faster as temperature When a cell’s oxide layer has degraded so much that it can no longer be sufficiently recharged, the testament to the effectiveness of the unique technologies, such as IntelligentScan + DataRefresh, growing in code size as drivers demand superior navigation and information systems, and passengers than in the larger enclosure of a typical free-standing SSD used as a computing accessory. rises, as Figure 2 shows. IntelligentScan function will repair it if possible, or retire it, thus avoiding any risk to data integrity. which Silicon Motion has developed for managing NAND Flash arrays. look for more entertainment options in the front and rear of the cabin. In vehicles, the long-term reliability and lifetime of an electronics component such as a mass storage To maintain reliable operation and data integrity in automotive storage devices, Silicon Motion applies The controller in Ferri products also implements advanced global wear leveling, so that P/E operations, The optimization of storage products for automotive applications results from Silicon Motion’s In functional terms, the car is becoming a data center on wheels – and like a data center, it needs device are crucial criteria. The automotive industry applies strict qualification tests, according to the various unique technologies which draw on its long experience in NAND Flash memory control. An and thus wear, are evenly allocated across an entire array. commitment to the automotive market – a commitment which is also demonstrated by its compliance high-speed access to a large data storage capacity. Reliability concerns have led automotive AEC-Q100 standard, to the integrated circuits used in automotive Electronic Control Units (ECUs), with understanding of these technologies will help the automotive system designer to evaluate NAND So this is the problem for NAND Flash-based storage devices for automotive applications such as the with the full range of automotive industry standards, including IATF 16949, ASPICE, and VDA 6.3. manufacturers to end the use of traditional Hard Disk Drive (HDD) storage devices, which offer a the aim of achieving zero defects over a long lifetime at temperatures of 85°C or higher. Flash-based storage devices with confidence that they are robust and reliable enough for use in infotainment system: in a car’s center console, an infotainment ECU might be required to operate at limited lifetime and are prone to mechanical failure. vehicles. temperatures as high as 85°C. But data loss is not acceptable in infotainment applications such as Automotive manufacturers can also take confidence from Silicon Motion’s leadership position in the The goal of reducing the component defect rate to zero is important because of the long lifetime of a mapping and navigation. And the AEC-Q100 standard mandates a defect rate of zero when tested at market for merchant SSD controllers and embedded storage devices. Silicon Motion is the leading vehicle, the high number of components in a vehicle, and the huge cost of rectifying a known fault in a NAND Flash cell operation at high temperature temperatures up to 85°C (for Grade 3 qualification). specialist manufacturer of NAND Flash controller technology, and can draw on more than 20 years’ fleet of vehicles which are in service – not to mention the reputational damage to a car maker’s brand. To see how technology can counter the effect of high temperatures on NAND Flash cells, it is important experience in developing specialized processor ICs which manage NAND components. In the past ten to understand the operation of these cells. In Flash memory, data bits are represented by stored It is a problem that a Silicon Motion storage controller, and the firmware which it runs, can solve. years, Silicon Motion has shipped more than six billion NAND Flash controllers, more than any other To illustrate the point simply, imagine a single Electronic Control Unit (ECU) consisting of 1,000 parts. charge (electrons) in cells. When NAND Flash technology first came on to the market, memory arrays company in the world. If the ECU manufacturer tolerated a defect rate as low as 1ppm, this single ECU alone would be were made of Single-Level Cell (SLC) elements. In SLC NAND, the cell stores one bit of data – a 1 or 0. Central role of storage controller responsible for 1,000 faults in a fleet of 1 million vehicles. And according to a 2019 report form analyst A NAND Flash-based storage system consists of two basic elements: So now automotive manufacturers can embed robust solid-state storage into infotainment and ADAS firm IHS Markit, a new luxury vehicle can contain as many as 150 ECUs1. As technology advanced, NAND Flash chip NAND Flash Types ECUs with confidence that Silicon Motion’s Ferri products’ lifetime, data integrity and data retention manufacturers responded to demand for higher will meet users’ expectations for vehicle lifetimes of ten years and beyond. This is why the automotive industry imposes the goal of a zero defect rate. And its strategy for reaching memory density by developing Multi-Level Cell SLC MLC TLC this goal is to apply a component qualification process, codified in the various AEC-Q10x standards. (MLC) technology, which stores two bits per cell, 111 The basic role of the controller is the bridge between the NAND Flash cells and the host processor 1 IHS Markit report cited at: 11 110 The criteria for AEC-Q100 qualification, for example, are extremely strict, and verify a component’s and then Triple-Level Cell (TLC) technology, with 1 101 which writes to and reads from the memory. The controller manages the mapping of bits to cell https://www.eenewsautomotive.com/news/number-automotive-ecus-continues-rise 10 100 reliability across a number of test parameters. The main reliability tests are: three bits per cell (see Figure 1). This means that 011 addresses. 01 010 the cell volume-per-bit has declined with each 0 001 00 000 new generation of NAND Flash. NAND cell size Silicon Motion has more than 20 years’ experience of developing the specialized controller ICs which 1 bit per cell 2 bits per cell 3 bits per cell Instead, automotive system designers today prefer to use a mass storage device which is based on also shrinks as semiconductor fabrication manage NAND components. Its deep understanding of NAND characteristics enables it to design both Fig. 1: NAND Flash chip manufacturers developed MLC technology, NAND Flash memory technology, such as a Solid State Disk (SSD), eMMC drive or UFS (Universal Flash processes advance from older process nodes to which stores two bits per cell, and then TLC technology, with three highly optimized ICs and related firmware controller platforms. In fact, more NAND Flash components, Storage) device. NAND Flash has become the preferred technology for mass storage in mobile phones, the latest sub-10nm nodes. bits per cell. including 3D Flash products from Intel, Kioxia, Micron, Samsung, SK Hynix, Western Digital and YMTC,

- 3 - laptop computers and other consumer devices as well as in SSDs because it offers a valuable The high memory density of today’s TLC NAND Flash devices means that a storage device such as are supported by Silicon Motion controllers than by those of any other company. Configuring NAND Flash cells for optimized operation combination of high memory density and high performance. This means that huge data storage Silicon Motion’s FerriSSD® can provide up to 480GB of data capacity in a surface-mount BGA package The controller embedded in Silicon Motion AEC-Q100 qualified storage devices also provides the capacity can be provided in a small packaged device, and the user benefits from rapid access to stored with a tiny footprint of just 20mm x 16mm. Silicon Motion’s understanding of the behavior of NAND Flash at high temperatures underlies the capability for the user to configure operation of TLC NAND Flash to extend data integrity. The SLCMode™ data and quick data storage operations. operation of its Ferri storage products, all of which are available in versions qualified to AEC-Q100 function available in Ferri products virtually groups together TLC or MLC cells into a one-bit SLC-like But the small size of TLC cells means that they wear out at a faster rate than SLC cells, a factor which Grades 3 and 2. configuration. This is ideal for use cases in which the nominal storage capacity (in TLC mode) is These characteristics are important as well to automotive manufacturers. But automotive applications the Flash controller embedded in a storage device has to take into account. Every Program/ Erase (P/E) over-specified. Operation with the SLCMode feature turned on reduces the nominal capacity, but gives impose special requirements which raise important additional questions about manufacturers’ choice cycle slightly degrades the oxide layer in the cells on which a P/E operation is performed. Smaller TLC Controller technology extends data retention SLC-like data retention and data integrity performance. of NAND storage device: cells have a thinner oxide layer than the larger SLC cells, so they degrade faster, and can on average As Figure 2 shows, the acceleration of electron leakage from NAND Flash memory cells at high withstand fewer P/E cycles. As this paper describes below, proprietary NANDXtend technology solve temperatures dramatically shortens data retention, down to as little as 2 days at 85°C for an MLC cell Ferri products offer MLCmode operation as well as SLCmode, giving users the ability to choose the This qualification process is exhaustive, and has been proved to effectively screen out potentially this problem in Ferri series storage devices. which has undergone its rated maximum number of P/E cycles. ideal balance between data integrity and capacity for their application. In addition, they provide an defective parts. Components which pass the tests and achieve AEC-Q100 qualification have SSDLifeGuard™ feature which automatically monitors the health status of the SSD, and triggers the demonstrated a remarkably high level of reliability and integrity in a demanding set of environmental NAND Flash cells also experience electron The Silicon Motion solution is to monitor the voltage at every cell in an array to detect those in which controller to implement data protection and error correction operations when blocks or pages are at risk. and application conditions. leakage over time. If too much charge leaks leakage has progressed to a critical state, and then to reprogram at-risk cells. The Ferri product feature from a cell, its data can no longer be read which implements this technology, IntelligentScan + DataRefresh, is capable of extending NAND Flash Extending NAND cell operation beyond ten years One of the most difficult elements of AEC-Q100 qualification for NAND Flash-based storage products out. ‘Data retention’ – the length of time for 40℃ array lifetimes far beyond the nominal P/E cycle lifetime specified by the Flash manufacturer (see AEC-Q100 qualification for automotive storage devices calls for zero-defect performance at high With the introduction of every new generation of passenger vehicle, the automation, safety and to achieve is to pass the high- temperature and accelerated lifetime simulation tests. Storage systems which data can be stored in a cell – declines 65℃ Figure 3). The intelligence in the IntelligentScan feature also includes responding automatically to temperature – a very challenging requirement for NAND Flash-based devices, because of the navigation systems become more sophisticated. Supported by an array of cameras, radar (RF) and must maintain reliable operation at continuous temperatures of up to 85°C for AEC-Q100 qualification as more P/E cycles are performed. And heat Data Retention Time temperature, and scanning more frequently when operating at high temperature. acceleration in data leakage from NAND cells at high temperatures of 85°C and above. The fact that 85℃ LiDAR (optical) ranging systems, sensors, and other detection systems, Advanced Driver Assistance to Grade 3, and up to 105°C for Grade 2. And the compact, chip-style packages in which the latest accelerates electron leakage, so data Silicon Motion’s Ferri products are qualified for automotive use at temperatures up to 105°C is Systems (ADAS) generate and process huge quantities of digital data. Infotainment systems, too, are products, such as Silicon Motion’s Ferri family, are housed, have more constrained thermal pathways retention also declines faster as temperature Spec When a cell’s oxide layer has degraded so much that it can no longer be sufficiently recharged, the testament to the effectiveness of the unique technologies, such as IntelligentScan + DataRefresh, P/E Cycles growing in code size as drivers demand superior navigation and information systems, and passengers than in the larger enclosure of a typical free-standing SSD used as a computing accessory. rises, as Figure 2 shows. IntelligentScan function will repair it if possible, or retire it, thus avoiding any risk to data integrity. which Silicon Motion has developed for managing NAND Flash arrays. Fig. 2: data retention in NAND Flash cells dramatically declines look for more entertainment options in the front and rear of the cabin. as temperature rises. (Image credit: Silicon Motion) In vehicles, the long-term reliability and lifetime of an electronics component such as a mass storage To maintain reliable operation and data integrity in automotive storage devices, Silicon Motion applies The controller in Ferri products also implements advanced global wear leveling, so that P/E operations, The optimization of storage products for automotive applications results from Silicon Motion’s In functional terms, the car is becoming a data center on wheels – and like a data center, it needs device are crucial criteria. The automotive industry applies strict qualification tests, according to the various unique technologies which draw on its long experience in NAND Flash memory control. An and thus wear, are evenly allocated across an entire array. commitment to the automotive market – a commitment which is also demonstrated by its compliance high-speed access to a large data storage capacity. Reliability concerns have led automotive AEC-Q100 standard, to the integrated circuits used in automotive Electronic Control Units (ECUs), with understanding of these technologies will help the automotive system designer to evaluate NAND So this is the problem for NAND Flash-based storage devices for automotive applications such as the with the full range of automotive industry standards, including IATF 16949, ASPICE, and VDA 6.3. manufacturers to end the use of traditional Hard Disk Drive (HDD) storage devices, which offer a the aim of achieving zero defects over a long lifetime at temperatures of 85°C or higher. Flash-based storage devices with confidence that they are robust and reliable enough for use in infotainment system: in a car’s center console, an infotainment ECU might be required to operate at limited lifetime and are prone to mechanical failure. vehicles. temperatures as high as 85°C. But data loss is not acceptable in infotainment applications such as Automotive manufacturers can also take confidence from Silicon Motion’s leadership position in the The goal of reducing the component defect rate to zero is important because of the long lifetime of a mapping and navigation. And the AEC-Q100 standard mandates a defect rate of zero when tested at market for merchant SSD controllers and embedded storage devices. Silicon Motion is the leading vehicle, the high number of components in a vehicle, and the huge cost of rectifying a known fault in a NAND Flash cell operation at high temperature temperatures up to 85°C (for Grade 3 qualification). specialist manufacturer of NAND Flash controller technology, and can draw on more than 20 years’ fleet of vehicles which are in service – not to mention the reputational damage to a car maker’s brand. To see how technology can counter the effect of high temperatures on NAND Flash cells, it is important experience in developing specialized processor ICs which manage NAND components. In the past ten to understand the operation of these cells. In Flash memory, data bits are represented by stored It is a problem that a Silicon Motion storage controller, and the firmware which it runs, can solve. years, Silicon Motion has shipped more than six billion NAND Flash controllers, more than any other To illustrate the point simply, imagine a single Electronic Control Unit (ECU) consisting of 1,000 parts. charge (electrons) in cells. When NAND Flash technology first came on to the market, memory arrays company in the world. If the ECU manufacturer tolerated a defect rate as low as 1ppm, this single ECU alone would be were made of Single-Level Cell (SLC) elements. In SLC NAND, the cell stores one bit of data – a 1 or 0. Central role of storage controller responsible for 1,000 faults in a fleet of 1 million vehicles. And according to a 2019 report form analyst A NAND Flash-based storage system consists of two basic elements: So now automotive manufacturers can embed robust solid-state storage into infotainment and ADAS firm IHS Markit, a new luxury vehicle can contain as many as 150 ECUs1. As technology advanced, NAND Flash chip ECUs with confidence that Silicon Motion’s Ferri products’ lifetime, data integrity and data retention A NAND Flash array A NAND Flash controller IC manufacturers responded to demand for higher will meet users’ expectations for vehicle lifetimes of ten years and beyond. This is why the automotive industry imposes the goal of a zero defect rate. And its strategy for reaching memory density by developing Multi-Level Cell this goal is to apply a component qualification process, codified in the various AEC-Q10x standards. (MLC) technology, which stores two bits per cell, The basic role of the controller is the bridge between the NAND Flash cells and the host processor 1 IHS Markit report cited at: The criteria for AEC-Q100 qualification, for example, are extremely strict, and verify a component’s and then Triple-Level Cell (TLC) technology, with which writes to and reads from the memory. The controller manages the mapping of bits to cell https://www.eenewsautomotive.com/news/number-automotive-ecus-continues-rise reliability across a number of test parameters. The main reliability tests are: three bits per cell (see Figure 1). This means that addresses. the cell volume-per-bit has declined with each new generation of NAND Flash. NAND cell size Silicon Motion has more than 20 years’ experience of developing the specialized controller ICs which Instead, automotive system designers today prefer to use a mass storage device which is based on also shrinks as semiconductor fabrication manage NAND components. Its deep understanding of NAND characteristics enables it to design both NAND Flash memory technology, such as a Solid State Disk (SSD), eMMC drive or UFS (Universal Flash processes advance from older process nodes to highly optimized ICs and related firmware controller platforms. In fact, more NAND Flash components, Storage) device. NAND Flash has become the preferred technology for mass storage in mobile phones, the latest sub-10nm nodes. including 3D Flash products from Intel, Kioxia, Micron, Samsung, SK Hynix, Western Digital and YMTC,

- 4 - laptop computers and other consumer devices as well as in SSDs because it offers a valuable The high memory density of today’s TLC NAND Flash devices means that a storage device such as are supported by Silicon Motion controllers than by those of any other company. Configuring NAND Flash cells for optimized operation combination of high memory density and high performance. This means that huge data storage Silicon Motion’s FerriSSD® can provide up to 480GB of data capacity in a surface-mount BGA package The controller embedded in Silicon Motion AEC-Q100 qualified storage devices also provides the capacity can be provided in a small packaged device, and the user benefits from rapid access to stored with a tiny footprint of just 20mm x 16mm. Silicon Motion’s understanding of the behavior of NAND Flash at high temperatures underlies the capability for the user to configure operation of TLC NAND Flash to extend data integrity. The SLCMode™ data and quick data storage operations. operation of its Ferri storage products, all of which are available in versions qualified to AEC-Q100 function available in Ferri products virtually groups together TLC or MLC cells into a one-bit SLC-like But the small size of TLC cells means that they wear out at a faster rate than SLC cells, a factor which Grades 3 and 2. configuration. This is ideal for use cases in which the nominal storage capacity (in TLC mode) is These characteristics are important as well to automotive manufacturers. But automotive applications the Flash controller embedded in a storage device has to take into account. Every Program/ Erase (P/E) over-specified. Operation with the SLCMode feature turned on reduces the nominal capacity, but gives impose special requirements which raise important additional questions about manufacturers’ choice cycle slightly degrades the oxide layer in the cells on which a P/E operation is performed. Smaller TLC Controller technology extends data retention SLC-like data retention and data integrity performance. of NAND storage device: cells have a thinner oxide layer than the larger SLC cells, so they degrade faster, and can on average As Figure 2 shows, the acceleration of electron leakage from NAND Flash memory cells at high withstand fewer P/E cycles. As this paper describes below, proprietary NANDXtend technology solve temperatures dramatically shortens data retention, down to as little as 2 days at 85°C for an MLC cell Ferri products offer MLCmode operation as well as SLCmode, giving users the ability to choose the This qualification process is exhaustive, and has been proved to effectively screen out potentially this problem in Ferri series storage devices. which has undergone its rated maximum number of P/E cycles. ideal balance between data integrity and capacity for their application. In addition, they provide an defective parts. Components which pass the tests and achieve AEC-Q100 qualification have SSDLifeGuard™ feature which automatically monitors the health status of the SSD, and triggers the demonstrated a remarkably high level of reliability and integrity in a demanding set of environmental NAND Flash cells also experience electron The Silicon Motion solution is to monitor the voltage at every cell in an array to detect those in which controller to implement data protection and error correction operations when blocks or pages are at risk. and application conditions. leakage over time. If too much charge leaks leakage has progressed to a critical state, and then to reprogram at-risk cells. The Ferri product feature from a cell, its data can no longer be read which implements this technology, IntelligentScan + DataRefresh, is capable of extending NAND Flash Extending NAND cell operation beyond ten years One of the most difficult elements of AEC-Q100 qualification for NAND Flash-based storage products out. ‘Data retention’ – the length of time for array lifetimes far beyond the nominal P/E cycle lifetime specified by the Flash manufacturer (see AEC-Q100 qualification for automotive storage devices calls for zero-defect performance at high With the introduction of every new generation of passenger vehicle, the automation, safety and to achieve is to pass the high- temperature and accelerated lifetime simulation tests. Storage systems which data can be stored in a cell – declines Figure 3). The intelligence in the IntelligentScan feature also includes responding automatically to temperature – a very challenging requirement for NAND Flash-based devices, because of the navigation systems become more sophisticated. Supported by an array of cameras, radar (RF) and must maintain reliable operation at continuous temperatures of up to 85°C for AEC-Q100 qualification as more P/E cycles are performed. And heat temperature, and scanning more frequently when operating at high temperature. acceleration in data leakage from NAND cells at high temperatures of 85°C and above. The fact that LiDAR (optical) ranging systems, sensors, and other detection systems, Advanced Driver Assistance to Grade 3, and up to 105°C for Grade 2. And the compact, chip-style packages in which the latest accelerates electron leakage, so data Silicon Motion’s Ferri products are qualified for automotive use at temperatures up to 105°C is Systems (ADAS) generate and process huge quantities of digital data. Infotainment systems, too, are products, such as Silicon Motion’s Ferri family, are housed, have more constrained thermal pathways retention also declines faster as temperature When a cell’s oxide layer has degraded so much that it can no longer be sufficiently recharged, the testament to the effectiveness of the unique technologies, such as IntelligentScan + DataRefresh, growing in code size as drivers demand superior navigation and information systems, and passengers than in the larger enclosure of a typical free-standing SSD used as a computing accessory. rises, as Figure 2 shows. IntelligentScan function will repair it if possible, or retire it, thus avoiding any risk to data integrity. which Silicon Motion has developed for managing NAND Flash arrays. look for more entertainment options in the front and rear of the cabin. In vehicles, the long-term reliability and lifetime of an electronics component such as a mass storage To maintain reliable operation and data integrity in automotive storage devices, Silicon Motion applies The controller in Ferri products also implements advanced global wear leveling, so that P/E operations, The optimization of storage products for automotive applications results from Silicon Motion’s In functional terms, the car is becoming a data center on wheels – and like a data center, it needs device are crucial criteria. The automotive industry applies strict qualification tests, according to the various unique technologies which draw on its long experience in NAND Flash memory control. An and thus wear, are evenly allocated across an entire array. commitment to the automotive market – a commitment which is also demonstrated by its compliance high-speed access to a large data storage capacity. Reliability concerns have led automotive AEC-Q100 standard, to the integrated circuits used in automotive Electronic Control Units (ECUs), with understanding of these technologies will help the automotive system designer to evaluate NAND So this is the problem for NAND Flash-based storage devices for automotive applications such as the with the full range of automotive industry standards, including IATF 16949, ASPICE, and VDA 6.3. manufacturers to end the use of traditional Hard Disk Drive (HDD) storage devices, which offer a the aim of achieving zero defects over a long lifetime at temperatures of 85°C or higher. Flash-based storage devices with confidence that they are robust and reliable enough for use in infotainment system: in a car’s center console, an infotainment ECU might be required to operate at 85 data retention simulation limited lifetime and are prone to mechanical failure. vehicles. temperatures as high as 85°C. But data loss is not acceptable in infotainment applications such as ℃ Automotive manufacturers can also take confidence from Silicon Motion’s leadership position in the 50 The goal of reducing the component defect rate to zero is important because of the long lifetime of a mapping and navigation. And the AEC-Q100 standard mandates a defect rate of zero when tested at market for merchant SSD controllers and embedded storage devices. Silicon Motion is the leading 45 Max ECC vehicle, the high number of components in a vehicle, and the huge cost of rectifying a known fault in a NAND Flash cell operation at high temperature temperatures up to 85°C (for Grade 3 qualification). Correctable specialist manufacturer of NAND Flash controller technology, and can draw on more than 20 years’ DataRefresh fleet of vehicles which are in service – not to mention the reputational damage to a car maker’s brand. To see how technology can counter the effect of high temperatures on NAND Flash cells, it is important 40 experience in developing specialized processor ICs which manage NAND components. In the past ten to understand the operation of these cells. In Flash memory, data bits are represented by stored It is a problem that a Silicon Motion storage controller, and the firmware which it runs, can solve. 35 years, Silicon Motion has shipped more than six billion NAND Flash controllers, more than any other

To illustrate the point simply, imagine a single Electronic Control Unit (ECU) consisting of 1,000 parts. charge (electrons) in cells. When NAND Flash technology first came on to the market, memory arrays 30 company in the world.

If the ECU manufacturer tolerated a defect rate as low as 1ppm, this single ECU alone would be were made of Single-Level Cell (SLC) elements. In SLC NAND, the cell stores one bit of data – a 1 or 0. Central role of storage controller 25 Preset / Programmable responsible for 1,000 faults in a fleet of 1 million vehicles. And according to a 2019 report form analyst A NAND Flash-based storage system consists of two basic elements: Error Bits Threshold So now automotive manufacturers can embed robust solid-state storage into infotainment and ADAS 20 firm IHS Markit, a new luxury vehicle can contain as many as 150 ECUs1. As technology advanced, NAND Flash chip ECUs with confidence that Silicon Motion’s Ferri products’ lifetime, data integrity and data retention 15 manufacturers responded to demand for higher will meet users’ expectations for vehicle lifetimes of ten years and beyond. This is why the automotive industry imposes the goal of a zero defect rate. And its strategy for reaching memory density by developing Multi-Level Cell 10 this goal is to apply a component qualification process, codified in the various AEC-Q10x standards. (MLC) technology, which stores two bits per cell, The basic role of the controller is the bridge between the NAND Flash cells and the host processor 5 1 IHS Markit report cited at:

The criteria for AEC-Q100 qualification, for example, are extremely strict, and verify a component’s and then Triple-Level Cell (TLC) technology, with which writes to and reads from the memory. The controller manages the mapping of bits to cell 0 https://www.eenewsautomotive.com/news/number-automotive-ecus-continues-rise 0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96 99 102 105 108 111 114 117 120 Month reliability across a number of test parameters. The main reliability tests are: three bits per cell (see Figure 1). This means that addresses. Based on 1Ynm MLC, @ 1,000 PE the cell volume-per-bit has declined with each IntelligentScan/DataRefresh to proactively extend Data new generation of NAND Flash. NAND cell size Silicon Motion has more than 20 years’ experience of developing the specialized controller ICs which Retention beyond the typical NAND flash limitation Not to scale, for illustration purpose Instead, automotive system designers today prefer to use a mass storage device which is based on also shrinks as semiconductor fabrication manage NAND components. Its deep understanding of NAND characteristics enables it to design both Fig. 3: the DataRefresh function increases the frequency of recharge operations as NAND Flash cells age. (Image credit: Silicon Motion) NAND Flash memory technology, such as a Solid State Disk (SSD), eMMC drive or UFS (Universal Flash processes advance from older process nodes to highly optimized ICs and related firmware controller platforms. In fact, more NAND Flash components, Storage) device. NAND Flash has become the preferred technology for mass storage in mobile phones, the latest sub-10nm nodes. including 3D Flash products from Intel, Kioxia, Micron, Samsung, SK Hynix, Western Digital and YMTC,

- 5 - laptop computers and other consumer devices as well as in SSDs because it offers a valuable The high memory density of today’s TLC NAND Flash devices means that a storage device such as are supported by Silicon Motion controllers than by those of any other company. Configuring NAND Flash cells for optimized operation combination of high memory density and high performance. This means that huge data storage Silicon Motion’s FerriSSD® can provide up to 480GB of data capacity in a surface-mount BGA package The controller embedded in Silicon Motion AEC-Q100 qualified storage devices also provides the capacity can be provided in a small packaged device, and the user benefits from rapid access to stored with a tiny footprint of just 20mm x 16mm. Silicon Motion’s understanding of the behavior of NAND Flash at high temperatures underlies the capability for the user to configure operation of TLC NAND Flash to extend data integrity. The SLCMode™ data and quick data storage operations. operation of its Ferri storage products, all of which are available in versions qualified to AEC-Q100 function available in Ferri products virtually groups together TLC or MLC cells into a one-bit SLC-like But the small size of TLC cells means that they wear out at a faster rate than SLC cells, a factor which Grades 3 and 2. configuration. This is ideal for use cases in which the nominal storage capacity (in TLC mode) is These characteristics are important as well to automotive manufacturers. But automotive applications the Flash controller embedded in a storage device has to take into account. Every Program/ Erase (P/E) over-specified. Operation with the SLCMode feature turned on reduces the nominal capacity, but gives impose special requirements which raise important additional questions about manufacturers’ choice cycle slightly degrades the oxide layer in the cells on which a P/E operation is performed. Smaller TLC Controller technology extends data retention SLC-like data retention and data integrity performance. of NAND storage device: cells have a thinner oxide layer than the larger SLC cells, so they degrade faster, and can on average As Figure 2 shows, the acceleration of electron leakage from NAND Flash memory cells at high withstand fewer P/E cycles. As this paper describes below, proprietary NANDXtend technology solve temperatures dramatically shortens data retention, down to as little as 2 days at 85°C for an MLC cell Ferri products offer MLCmode operation as well as SLCmode, giving users the ability to choose the This qualification process is exhaustive, and has been proved to effectively screen out potentially this problem in Ferri series storage devices. which has undergone its rated maximum number of P/E cycles. ideal balance between data integrity and capacity for their application. In addition, they provide an defective parts. Components which pass the tests and achieve AEC-Q100 qualification have SSDLifeGuard™ feature which automatically monitors the health status of the SSD, and triggers the demonstrated a remarkably high level of reliability and integrity in a demanding set of environmental NAND Flash cells also experience electron The Silicon Motion solution is to monitor the voltage at every cell in an array to detect those in which controller to implement data protection and error correction operations when blocks or pages are at risk. and application conditions. leakage over time. If too much charge leaks leakage has progressed to a critical state, and then to reprogram at-risk cells. The Ferri product feature from a cell, its data can no longer be read which implements this technology, IntelligentScan + DataRefresh, is capable of extending NAND Flash Extending NAND cell operation beyond ten years One of the most difficult elements of AEC-Q100 qualification for NAND Flash-based storage products out. ‘Data retention’ – the length of time for array lifetimes far beyond the nominal P/E cycle lifetime specified by the Flash manufacturer (see AEC-Q100 qualification for automotive storage devices calls for zero-defect performance at high With the introduction of every new generation of passenger vehicle, the automation, safety and to achieve is to pass the high- temperature and accelerated lifetime simulation tests. Storage systems which data can be stored in a cell – declines Figure 3). The intelligence in the IntelligentScan feature also includes responding automatically to temperature – a very challenging requirement for NAND Flash-based devices, because of the navigation systems become more sophisticated. Supported by an array of cameras, radar (RF) and must maintain reliable operation at continuous temperatures of up to 85°C for AEC-Q100 qualification as more P/E cycles are performed. And heat temperature, and scanning more frequently when operating at high temperature. acceleration in data leakage from NAND cells at high temperatures of 85°C and above. The fact that LiDAR (optical) ranging systems, sensors, and other detection systems, Advanced Driver Assistance to Grade 3, and up to 105°C for Grade 2. And the compact, chip-style packages in which the latest accelerates electron leakage, so data Silicon Motion’s Ferri products are qualified for automotive use at temperatures up to 105°C is Systems (ADAS) generate and process huge quantities of digital data. Infotainment systems, too, are products, such as Silicon Motion’s Ferri family, are housed, have more constrained thermal pathways retention also declines faster as temperature When a cell’s oxide layer has degraded so much that it can no longer be sufficiently recharged, the testament to the effectiveness of the unique technologies, such as IntelligentScan + DataRefresh, growing in code size as drivers demand superior navigation and information systems, and passengers than in the larger enclosure of a typical free-standing SSD used as a computing accessory. rises, as Figure 2 shows. IntelligentScan function will repair it if possible, or retire it, thus avoiding any risk to data integrity. which Silicon Motion has developed for managing NAND Flash arrays. look for more entertainment options in the front and rear of the cabin. In vehicles, the long-term reliability and lifetime of an electronics component such as a mass storage To maintain reliable operation and data integrity in automotive storage devices, Silicon Motion applies The controller in Ferri products also implements advanced global wear leveling, so that P/E operations, The optimization of storage products for automotive applications results from Silicon Motion’s In functional terms, the car is becoming a data center on wheels – and like a data center, it needs device are crucial criteria. The automotive industry applies strict qualification tests, according to the various unique technologies which draw on its long experience in NAND Flash memory control. An and thus wear, are evenly allocated across an entire array. commitment to the automotive market – a commitment which is also demonstrated by its compliance high-speed access to a large data storage capacity. Reliability concerns have led automotive AEC-Q100 standard, to the integrated circuits used in automotive Electronic Control Units (ECUs), with understanding of these technologies will help the automotive system designer to evaluate NAND So this is the problem for NAND Flash-based storage devices for automotive applications such as the with the full range of automotive industry standards, including IATF 16949, ASPICE, and VDA 6.3. manufacturers to end the use of traditional Hard Disk Drive (HDD) storage devices, which offer a the aim of achieving zero defects over a long lifetime at temperatures of 85°C or higher. Flash-based storage devices with confidence that they are robust and reliable enough for use in infotainment system: in a car’s center console, an infotainment ECU might be required to operate at limited lifetime and are prone to mechanical failure. vehicles. temperatures as high as 85°C. But data loss is not acceptable in infotainment applications such as Automotive manufacturers can also take confidence from Silicon Motion’s leadership position in the The goal of reducing the component defect rate to zero is important because of the long lifetime of a mapping and navigation. And the AEC-Q100 standard mandates a defect rate of zero when tested at market for merchant SSD controllers and embedded storage devices. Silicon Motion is the leading vehicle, the high number of components in a vehicle, and the huge cost of rectifying a known fault in a NAND Flash cell operation at high temperature temperatures up to 85°C (for Grade 3 qualification). specialist manufacturer of NAND Flash controller technology, and can draw on more than 20 years’ fleet of vehicles which are in service – not to mention the reputational damage to a car maker’s brand. To see how technology can counter the effect of high temperatures on NAND Flash cells, it is important experience in developing specialized processor ICs which manage NAND components. In the past ten to understand the operation of these cells. In Flash memory, data bits are represented by stored It is a problem that a Silicon Motion storage controller, and the firmware which it runs, can solve. years, Silicon Motion has shipped more than six billion NAND Flash controllers, more than any other To illustrate the point simply, imagine a single Electronic Control Unit (ECU) consisting of 1,000 parts. charge (electrons) in cells. When NAND Flash technology first came on to the market, memory arrays company in the world. If the ECU manufacturer tolerated a defect rate as low as 1ppm, this single ECU alone would be were made of Single-Level Cell (SLC) elements. In SLC NAND, the cell stores one bit of data – a 1 or 0. Central role of storage controller responsible for 1,000 faults in a fleet of 1 million vehicles. And according to a 2019 report form analyst A NAND Flash-based storage system consists of two basic elements: So now automotive manufacturers can embed robust solid-state storage into infotainment and ADAS firm IHS Markit, a new luxury vehicle can contain as many as 150 ECUs1. As technology advanced, NAND Flash chip ECUs with confidence that Silicon Motion’s Ferri products’ lifetime, data integrity and data retention manufacturers responded to demand for higher will meet users’ expectations for vehicle lifetimes of ten years and beyond. This is why the automotive industry imposes the goal of a zero defect rate. And its strategy for reaching memory density by developing Multi-Level Cell this goal is to apply a component qualification process, codified in the various AEC-Q10x standards. (MLC) technology, which stores two bits per cell, The basic role of the controller is the bridge between the NAND Flash cells and the host processor 1 IHS Markit report cited at: The criteria for AEC-Q100 qualification, for example, are extremely strict, and verify a component’s and then Triple-Level Cell (TLC) technology, with which writes to and reads from the memory. The controller manages the mapping of bits to cell https://www.eenewsautomotive.com/news/number-automotive-ecus-continues-rise reliability across a number of test parameters. The main reliability tests are: three bits per cell (see Figure 1). This means that addresses. the cell volume-per-bit has declined with each new generation of NAND Flash. NAND cell size Silicon Motion has more than 20 years’ experience of developing the specialized controller ICs which For more information about Ferri Family, please go to Instead, automotive system designers today prefer to use a mass storage device which is based on also shrinks as semiconductor fabrication manage NAND components. Its deep understanding of NAND characteristics enables it to design both www.siliconmotion.com or send email to [email protected] NAND Flash memory technology, such as a Solid State Disk (SSD), eMMC drive or UFS (Universal Flash processes advance from older process nodes to highly optimized ICs and related firmware controller platforms. In fact, more NAND Flash components, © Copyright 2021 Silicon Motion, Inc. Storage) device. NAND Flash has become the preferred technology for mass storage in mobile phones, the latest sub-10nm nodes. including 3D Flash products from Intel, Kioxia, Micron, Samsung, SK Hynix, Western Digital and YMTC, FERRI-WP-202105

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