LM74704-Q1: Can 'Large' FETs with high total gate capacitance be used?

Senthil Seveelavanan18

Part Number: LM74704-Q1

Tool/software:

Hello,

I want to use this FET with large requires high capacitance attributes.
https://www.digikey.be/en/products/detail/analog-power-inc/AM90N08-04B/23019514

Total Gate Charge = 167 nC
Reverse Transfer Capacitance Crss = 970 pF

I can't find anything in the datasheet comments on selection criteria based on capacitance attributes.

Are there any implicit timers/mechanisms expect FETs of a certain size, which would therefore have problems with 'larger' FETs.

Thanks

7 months ago

0 Shiven Dhir 7 months ago

TI__Mastermind 49455 points

Hi Senthil,

With change is MOSFET properties, you can scale the charge pump capacitor of the controller according to the equation below.

Regards,

Shiven Dhir.

0 Senthil Seveelavanan18 7 months ago in reply to Shiven Dhir

Prodigy 160 points

Hi Shiven,

Great, so no implicit or explicit limits on the FET : )

Whilst I have your help, to work through the value of VCAP

Ciss for the above linked FET AM90N08-04B is 11678 pF = 11.7 nF.
Recommend value of VCAP is ~117 nF for VCAP.

Just to confirm, that recommended value is the best value, and so no benefit to going higher, say 220nF?

Thanks again

0 Shiven Dhir 7 months ago in reply to Senthil Seveelavanan18

TI__Mastermind 49455 points

Hi Senthil,

There is no benefit in increasing the cap value. Although closest standard value might be 220nF only.

Regards,

Shiven Dhir

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LM74704-Q1: Can 'Large' FETs with high total gate capacitance be used?