LM3481-FLYBACKEVM: FET selection

PAN-M

Part Number: LM3481-FLYBACKEVM
Other Parts Discussed in Thread: LM3481, PMP10725, , CSD19532Q5B, CSD19502Q5B, CSD19538Q3A

Dear all.

I examine Flyback by LM3481.
CSD19502Q5B and CSD19532Q5B are used for each of LM3481-FlybackEVM and PMP10725.
These IDM is 400A.
Is these big spec necessary?
Can I use CSD19538Q3A?

Regards,
PAN-M

over 7 years ago

0 Youhao Xi over 7 years ago

TI__Guru* 78070 points

The MOSFET is normally selected by it Rds(ON) and other switching parameters like Qg, Coss, etc, not by the current rating.

0 PAN-M over 7 years ago in reply to Youhao Xi

Mastermind 8375 points

Please teach me the necessary parameter(Qg/Coss/etc.) in LM3481.
Can I use CSD19538Q3A by 5W design?

0 Youhao Xi over 7 years ago in reply to PAN-M

TI__Guru* 78070 points

These are fundamentals of power electronics but cannot be explained in a short msg. Please refer to a text book or take a course on power electronics.

Regarding your selection, it should work for your 5W design, but there may be better selections depending on your operating conditions: Vin, Vout, switching frequency, etc.

Thanks,

Power management

Power management forum

LM3481-FLYBACKEVM: FET selection