Inductors for Class-D Audio Amplifiers

Based on their miniaturized package size and For high-power Class-D amplifiers (>50 Watts), high efficiency, Class-D power amplifiers have selecting the right inductor for the output LC become increasingly popular replacements filter plays a critical role in improving the effi- for linear amplifiers in many high-end audio ciency and overall sound quality of the system. system applications.

Dual Inductors for Ultra-low Distortion Class-D Amplifiers

Product Overview: Design Features UA8013-AL / UA8014-AL / RA7231-AL • Designed into Texas Instruments’ TPA3220 (50 W Stereo), TPA3244 (60 W Stereo) and Coilcraft offers a unique selection of dual inductors that TPA3245 (115 W Stereo) Class-D Amplifier significantly improve the performance of the output LC evaluation modules filter and reduce the board area with a compact sin- • Also suitable for TI’s TPA3251 (175 W Stereo) gle shielded package. Good linearity of the inductors’ Class-D Amplifier saturation current and ultra low total losses minimize the • Dual inductors in a single shielded package to save impact of total harmonic distortion plus noise (THD+N), circuit board space greatly improving audio quality. • Very low coupling coefficient (k<0.001), minimal Applications crosstalk between the two inductors • Handheld audio devices & portable docking stations • Excellent inductance vs. current linearity up to 10 A • High-end TV soundbars • Economical solutions for a wide variety of audio • Active speakers and subwoofers amplifier applications • Automotive stereo audio systems • RA7231-AL: AEC-Q200 Grade 1 qualified (-40°C to +125°C ambient)

Inductance DCR Max SRF typ Isat (A) Irms (A) Part Number ±10% (µH) (mOhms) (MHz) 10% drop 20% drop 30% drop 20°C rise 40°C rise L1 7.0 6.6 40 12.0 12.5 13.2 UA8013-AL_ 6.5 9.0 L2 7.0 6.6 40 12.0 12.5 13.2 L1 10.0 6.6 28 8.7 9.1 9.4 UA8014-AL_ 6.5 9.0 L2 10.0 6.6 28 8.7 9.1 9.4 L1 5.0 6.0 34 15.5 16.6 17.6 RA7231-AL_ 7.6 10.6 L2 5.0 6.0 34 15.5 16.6 17.6 Inductors for Class-D Audio Amplifiers Dual Inductors for Ultra-low Distortion Class-D Amplifiers (continued) L vs. Current TI’s TPA3244/3245 60W/115W Stereo Pure- 100 Path™ Ultra-HD, Analog-In Class-D Amplifier UA8013-AL UA8014-AL RA7231-AL

L1 Vout A

(µH) L2 Vout B UA8014-AL 10 TPA3244 TPA3245 UA8013-AL L1

Inductance RA7231-AL Vout A

L2 Vout B

UA8013-AL 1 UA8014-AL 0.1 1 10 100 RA7231-AL Current (A) inches Dimensions mm

Dot indicatesDot pin indicates 1 pin 1

UA801X-AL 14

UA801X-AL

XXXX 14

XXXX 0.630 0.551 max max 16,00 L1 L2 14,00 0.630

Y 0.551 max max 16,00 L1 L2 14,00 23

Y

0.004 /0,10 23 0.610 max 15,50 0.004 /0,10 0.610 max 15,50

Single Power Inductors for TI Automotive Class-D Audio Amplifier CL 0.224 0.047 0.094 5,7 1,2 2,4 0.122 3,1 Coilcraft2 provides3 a complete solution for the PMP11769 L5_1, L5_2 10 µH SER2918H-103KL C CLL 0.227004 Watt0.047 automotive0.094 Class-D audio amplifier reference L6_1, L6_2 10 µH SER2918H-103KL 5,7 1 1,2 4 2,4 0.122 Class-D Amplifier Output LC Filter 0.122 3,1 design from Texas3,1 Instruments. Our SER2918H-103 (Left and right channel) 2 0.248 3 0.071 L7_1, L7_2 10 µH SER2918H-103KL 6,3 1,8 CL power inductor is used for the output LC filter which L8_1, L8_2 10 µH SER2918H-103KL Recommended 1convertsLand the Pa4 ttern PWM output into a continuous low noise L1 330 µH LPS6235-334MLB 0.303 0.1220.126 7,7 3,1 3,2 0.134 0.248 0.071 3,4 0.102 analog signal to achieve2,6 great performance. It is also Buck Power Stage L2, L4 500 nH XPL2010-501MLB 6,3 1 1,8 4

usedC Lwith other Coilcraft parts in the Buck and Boost L3 1 mH LPS4012-105MLB Recommended 2 3 powerLand Pa tternstages (see0.102 table). L9 10 µH SER2918H-103KL 2,6 0.303 0.209 0.1260.031 Boost Power Stage 7,7 5,3 3,20,8 CL 0.134 L11 10 µH SER2918H-103KL 3,4 0.102 Design Features 2,6 1 4

CL • Easily integrated into automotive systems with 50V

2 load dump3 and integrated protection system 0.102 2,6 0.209 0.031 5,•3 Ultra-HD0,8 audio for best quality sound for any integratedCL Class-D amplifier • 100kHz bandwidth, which enables support for high resolution audio files and formats • Low noise eliminates “hiss” or “buzz” sounds

Photo courtesy of Texas Instruments, Inc. www.coilcraft.com Document 1404 Revised 3/1/18