LM3481: PMP20981.1 reference design questions

Julian Chen

Expert 2550 points

Part Number: LM3481

Dear E2E member,

I use PMP20981.1 and have some question as below,

1. What function of R1, C3 and D1?

2. If we R1 want to use 0.5W solution, is it OK?

Thanks!

over 7 years ago

0 Youhao Xi over 7 years ago

TI__Guru* 78190 points

Its a snubber circuit. My recommendation is to reserve the position for a larger resistor in case it is really needed. Otherwise you will have to do another PCB design.

0 Julian Chen over 7 years ago in reply to Youhao Xi

Expert 2550 points

Dear Youhao,

Thanks for your reply.

I have another question, does R4 and C13 are also snubber circuit?

0 Garrett Roecker over 7 years ago in reply to Julian Chen

TI__Mastermind 21720 points

Hi Julian,

Yes, R4 and C13 also form a snubber. This snubber is used to reduce the ringing on the secondary side.

-Garrett

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LM3481: PMP20981.1 reference design questions