NFET can take 30V VGS?

[cupoftea]

Hi,
On page one of the SPW47N60 NFET datasheet, it says it can handle a gate drive voltage of +/-30V AC at >=1Hz.
So does that mean we can drive it indefinetely with a voltage of 25V for 900ms, then 0V for 100ms.....repeatedly for years, and no damage will occur to the gate?

SPW47N60 datasheet

https://www.infineon.com/dgdl/Infineon-SPW47N60C3-DS-v02_06-en.pdf?fileId=db3a304412b407950112b42dff93492f

 

[FvM]

Why would you intentionally driver higher gate voltage than +/- 20V?

 

[cupoftea]

Why would you intentionally driver higher gate voltage than +/- 20V?

Thanks, i have a 1kW Boost PFC schem which has a strange looking gate "snubber"....this is obviously because they expect transient voltages above 20V.
But the datasheet says it can handle up to 30V if its AC...so i was wondering of the attached snubber is a bit "overkill"?
I mean, presumably it can handle gate voltage spikes up to 30V?...because they are effectively AC?....or have an AC content, should i say.

 

[Vbase]

Sometimes inductive load on the drain causes large transients. The internal cap between the drain and the gate causes the gate voltage to rise above 30V, the zener snubber suppose to protect the gate. Some datasheets recommend it and some IR mosfets have integrated zeners.

 

[dick_freebird]

This all depends on the physics of failure which you don't get to know.

To me, 30V @>1Hz means 50% duty equating to 15V DC stress over time (neglecting any element of reversibility in whatever is the deciding mechanism).

That is what I'd criticize any time averaged gate voltage figuring, against.