Mosfet Vgs +- rating

[Craftplorer]

Hi,
i was looking at following mosfet from Fairshield https://www.mouser.de/datasheet/2/308/FDBL0065N40-1305438.pdf or from On Semi https://www.mouser.de/datasheet/2/308/NTMFS5C404N-D-1067128.pdf. Both have a Vgs of +-20V so does it mean that I can only apply 10V to the gate?

[ajb]

No, that means you can apply an absolute maximum of +20V or -20V to the gate, relative to the source.  I'm not sure how you got 10V from that. 

However, it is not wise to use design your project based on absolute maximum ratings, as this leaves you no margin for error.  Electrical noise, or component tolerances, or other factors can easily push your device over the edge and cause damage to components.  Generally, MOSFET gates are driven to 10-12V in situations where you want hard switching and low on resistance.  This leaves a fair margin between the operating conditions and the absolute maximum ratings of typical transistors.

[Benta]

It means you can apply +20 V or -20 V to the the gate without destroying the device.
Designing to the maximum rating is not a good idea, though, I'd go to +/-15 V tops.

[Benta]

Whoops, simultaneous posting. At least we agree

[Craftplorer]

Thank.
I was confused because opamp often say +-36V for dual supply but after i thought about it, it makes sense to me
And of cource i didn't want to drive the fet with 20V. The project ist powered by 11.4v

[HB9EVI]

you cannot conclude from an opamp to a FET - these are two complete different devices.
actually 36V is the absolute maximum rating for most jellybean opamps, the normal operational range is +/-15V

don't orient you on the absolute maximum ratings, they should never be touched under normal operating conditions

[perieanuo]

Thank.
I was confused because opamp often say +-36V for dual supply but after i thought about it, it makes sense to me
And of cource i didn't want to drive the fet with 20V. The project ist powered by 11.4v

Hi, your 11.4 volts don't count.you can have a spike from another pcb sitting next to yours or induction or.. or..
That's why every power mosfet have some 12-15V zener protecting gate-source junction.don't miss this on power boards with mosfets as final stage.
Regards,pierre


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