LM25122-Q1: schematic design questions

Betty Guo

Expert 7300 points

Part Number: LM25122-Q1
Other Parts Discussed in Thread: TIDA-01610

Hi team,

we would use LM25122-Q1 to power supply Class-D. the audio output power is 80W*2=160W max. voltage is 18V.

we reference to the TIDA-01610. In this TIDA scheamtic, use two LM25122-Q1, the second filter use a L3. see the below.

My questions is what's the function of L3? can we remove it? if no, how to select this inductor parameters? Thank you

https://www.ti.com/lit/ug/tidudu1/tidudu1.pdf

over 3 years ago

0 EM over 3 years ago

TI__Genius 11215 points

Hello Betty,

Thanks for the question. Since audio amplifiers are sensitive to noise and output ripple, the L3 in the design is acting as an LC filter together with the output caps (Butterworth 2nd order filter). At the following link you can find more info on how to design such a filter https://e2e.ti.com/blogs_/b/powerhouse/posts/design-a-second-stage-filter-for-sensitive-applications

Let me know if I can help you furthermore.

Kind regards,

Elisabetta

0 EM over 3 years ago in reply to EM

TI__Genius 11215 points

Hello Betty,

I haven’t heard back from you, so I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if this one has been locked due to time-out).

Thanks,

Elisabetta

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LM25122-Q1: schematic design questions