Capacitance of gate protection zener diode?

[cupoftea]

Hi,
Wishing to use one of these DO41 18V zeners on our FET gate of our2kW LLC converter to prevent overvoltage to the gate....

https://www.farnell.com/datasheets/3449664.pdf

..Do you know what is its capacitance?.......(capacitance when its got near 0V to 4V [Vgsth] on it.)

 

[FvM]

What to do if a particular datasheet doesn't specify a parameter of interest?
- refer to more detailed datasheets of similar components
- check if they can be derived from other data, e.g. SPICE models. I guess you already know.

 

[KlausST]

Hi,

.. or measure it.

Klaus

 

[danadakk]

Looks like its ~ 30 pF. If this is a clamp for a MOSFET gate typically 30
pF is negligible compared to the MOSFET C and its miller C.

https://www.diodes.com/assets/Datasheets/ds18007.pdf

if you are using a series gate R to damp ringing this might help -

https://toshiba.semicon-storage.com/info/docget.jsp?did=59460

Regards, Dana.

 

[cupoftea]

Thanks for that zener datasheet...its troubling it doesnt show capacitance for <5V, because thats the bit below Vgsth, ....as you suggest, some capacitance is ok there, but not too much.

https://www.diodes.com/assets/Datasheets/ds18007.pdf

 

[danadakk]

Looks like you will have to measure, attached a discussion of test jig.

From attached book -

Regards, Dana.