LTC7004 dV/dt imunity?

Hello everyone.

I tried to use LTC7004 to drive MOSFETs on a specific application: Drain/source of the MOSFET is not tied to a specific voltage. dV/dt is close to 40V/10ns.

I noticed that:

   - There is no dV/dt specified in the datasheet.

   - There is lot of capacitance added on the demo board DC2750A (100uF) without explanations.

When I try to simulate such dV/dt when the gate is already driven (INP=1, TG-TS=12V), there is lot of perturbations on TG-TS that can cross AMR (>16V) or go down and bad drive the MOSFET!!!

Adding capacitance to the ground as my voltage source dV/dt is weak imperance seems not usefull...

Is LTC7004 good for such dV/dt?

Do you have any suggestions to improve dV/dtimunity?

Should I use another isolated gate driver to avoid this?

I like LTC7004 for this low power consuption and static use. Standard gate drivers with charge pump generally use the fact the source is put to ground at duty cycle and I dont in my application. Isolated gate drivers is a good solution but power consuption is often high.

Thank you for your answers.

Parents Reply
  • Thank you for your answer.

    The only difference between both schematics is the MOSFET lib importation... And it make the difference!?!

    I tried to do like you by adding a .lib command instraed of creating a new symbol (with the same library of course). And it woks fine.

    I dont know the difference but there is one...

    I tried with differents MOSFET and there is no overshoots too.

    Problem solved! Thank you!

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