TPS56428: Outcap value

allen

Intellectual 360 points

Part Number: TPS56428

Dear Sir

I have use TPS56428 at 12V to 5V for USB port.

can I put 470uf cap at output side?

or any recommend for Max output cap value?

allen

over 7 years ago

0 Vental Mao over 7 years ago

TI__Expert 5745 points

The value of Cout in the datasheet is the 20uF~68uF, so you had better do not use the 470uF. Bigger cap means smaller cross frequency which will cause unstable.

Besides, is the 470uF Electrolytic capacitor？ The TPS56428 is DCAP2 -mode, the ceramic capacitor or low ESR cap is better.

0 allen over 7 years ago in reply to Vental Mao

Intellectual 360 points

Hi Quote

Yes, 470uF is Electrolytic capacitor.

Our design need supply 5V to USB port, and USB port need input cap bigger than 120uF, if we put 120uF ceramic capacitor at TPS56428 output side is that OK?

Allen

0 Vental Mao over 7 years ago in reply to allen

TI__Expert 5745 points

yes, 120uF is ok, but the transient performance will be not very good. Thank you!

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TPS56428: Outcap value