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LTspice Wolfspeed mosfet model doesn't seem to be working

Cecemel

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Hi,

I've set up a simple circuit in LTspice using a model of Wolfspeed's C3M0075120K. I'm feeding the gate a square wave but I'm only seeing tiny current spikes at rise and fall going through the mosfet.

This probably isn't the ideal way to drive a mosfet, but it's just a simple test I set up after discovering the problem while trying to drive a half-bridge using a model of the UCC21520 isolated gate driver (it worked fine until I swapped the existing mosfets for these ones).

Am I doing something wrong or should I contact Wolfspeed?

Datasheet: C3M0075120K

Circuit: View attachment files.zip

Screenshot.png
 

frankrose

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Connect disconnected pins too (Tj Tc). Don't let them floating. I see 2.4A if they are grounded.
 

KlausST

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Hi,

try to connect V1 Minus directely to GND instead of KS.

Klaus
 

Cecemel

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Thanks for your replies.

Connecting Tj and Tc to ground fixed my issue. I thought I could leave them floating because when searching the internet for a fix, I came across this manual. On page 7, it says Tj can be left floating, and it says Tc can be left floating, but I failed to read the highlighted note which says one of them should be connected to a voltage source.
 

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