Three-Terminal Capacitor Structure 17 (A) Structure of Capacitors Two-Terminal Capacitor Three-Terminal Capacitor Dielectric Dielectric

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This is the PDF file of text No.TE04EA-1. No.TE04EA-1.pdf 98.3.20

3. Noise Suppression by Low-pass Filters 3.7. Improvement of High-frequency Characteristic

Three-terminal Capacitor Structure 17 (a) Structure of capacitors Two-terminal capacitor Three-terminal capacitor Dielectric Dielectric

Electrode Electrode

Lead Lead

(b) Equivalent circuit with considerations for ESL Signal current Signal current

Leaded disc ceramic capacitor (1000pF) 40 Leaded three-terminal ceramic capacitor with built-in ferrite beads (DSS306-55B102M:1000pF)

Insertion loss (dB) 60 Leaded three-terminal ceramic capacitor (DS306-55B102M: 1000 pF) Ideal characteristic of capacitor 80 1 5 10 50 100 500 1000 2000 Frequency (MHz)

With leaded two-terminal capacitors, the residual inductance is [Notes] larger because the lead wires work as inductors. By making the three terminal structure ,the residual inductance in series with capacitance become lower .Therefore the insertion loss is better than two terminal capacitors.

–– 17 –– This is the PDF file of text No.TE04EA-1. No.TE04EA-1.pdf 98.3.20

3. Noise Suppression by Low-pass Filters 3.7. Improvement in High-frequency Characteristic of Capacitors Chip Type Three-terminal Capacitors 18 (a) Structure of capacitors Chip two-terminal capacitor Chip three-terminal capacitor

Ground terminal Ground terminal I/O terminal

Input and Output terminal Input and Output terminal

Ground terminal

Electrode pattern Electrode pattern

(b) Improvement results of insertion loss characteristic 0

Leaded disc ceramic capacitor (1000 pF) 40 Chip monolithic ceramic capacitor (1000 pF) 2.0 x 1.25 x 0.6 mm Leaded three-terminal capacitor 60 Insertion loss (dB) (DS306-55B102M: 1000 pF) Chip three-terminal capacitor (NFM40R11C102: 1000 pF) 80 3.2 x 1.25 x 0.7 mm 1 5 10 50 100 500 1000 2000 Frequency (MHz)

The structural model of the chip three-terminal capacitor is shown [Notes] above. An electrode pattern is printed on each dielectric sheet. Input and output terminals are provided on both ends and are connected using the electrode pattern. This structure allows the signal current to pass through the capacitor.The residual inductance on the ground terminal is reduced with ground terminals on both sides. This structure makes an extremely low residual inductance, which provides a higher self-resonance frequency.

–– 18 –– This is the PDF file of text No.TE04EA-1. No.TE04EA-1.pdf 98.3.20

3. Noise Suppression by Low-pass Filters 3.7. Improvement in High-frequency Characteristic of Capacitors

Feedthrough Capacitors 19

(a) Structure of capacitors Three-terminal capacitor Feedthrough capacitor

Dielectric Shielding plate Electrode

Dielectric

Lead Feedthrough terminal Ground electrode

(b) Improvement results of insertion loss characteristic

40 Leaded disc ceramic capacitor (1000 pF) Leaded disc three-terminal ceramic capacitor (DS306-55B102M: 1000 pF)

Insertion loss (dB) 60 Feedthrough ceramic capacitor (DF553: 1000 pF)

80 1 5 10 50 100 500 1000 2000 Frequency (MHz)

Feedthrough capacitors have a structure in which the ground [Notes] electrode surrounds the dielectric and the signal terminal goes through the dielectric. Feedthrough capacitors are used by making a mounting hole in the shielding case and soldering the ground electrode directly to the shielding case (plate). Since this type of capacitor has no residual inductance on the ground terminal side as well as on the signal terminal side, it can provide nearly ideal insertion loss characteristics.

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