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Original question:

TPS65131-Q1: Schematic/application review

TPS65131: TPS65131 switching nose issue at negative output

Gary Teng
Genius 5520 points
Part Number: TPS65131

Tool/software:

Hi Sir,

 My customer use TPS65131 for 4V to +- 5.5V application. (power for LCM module with aroung 20mA current spent). It's +5.5V output looks fine, but -5.5V has 1V switching noise.

Without load:

With load:

Custiner do some tests:

1. modify some setting (mark as red words): failed.

2. change inductor to 10uH 900mA: failed.

3. Put 200uF capacitor parallel with C261: ok

4. Change input voltage form 4V to 3.7V: ok

Is there any suggestion for improving the negative output ripple? Or anything we have to check at customer board?

Thanks for your kindly help.

Best regards,

Gary Teng