MOSFET capacitance clarification

Question

Two part question here:

Are there ways to directly test the input and output capacitance of a MOSFET, Ciss and Coss?
Due to internal inductance and capacitance, is it possible for a standalone MOSFET to resonate at certain frequencies?

score 1 · Accepted Answer · answered Jul 03 '19 at 19:44

YES,YES 1) See best datasheets for test methods.

2) All traces have ESL starting at ~0.5nH/mm and scope probes are also notorious for ground ESL resonance with 10:1 coax xx pF, for resonance <50 MHz, thus tip/ring method is best between to nearby pins <1cm apart with gnd clip and probe tip both removed.

score 0 · Answer 2 · answered Jul 04 '19 at 05:15

0

Depending on the FET fabrication method, you may find Rgate and Rsubstrate are adequate to dampen the resonances.

answered Jul 04 '19 at 05:15

analogsystemsrf

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MOSFET capacitance clarification

2 Answers2