TPS51200: TPS51200 INPUT Capacitor

Wenhao Wu

Part Number: TPS51200

Hi Qian,

Regarding TPS51200, our datasheet specifies that INPUT capacitance of TPS51200 VINLDO must be larger than 1/2 OUTPUT capacitance. My customer wants to use 10uF+2.2uF capacitance combination for TPS51200 because they want to shrink solution size further. Except input cap is different, they are using below schematic. The load is only one DDR4.

Could you please check if 12.2uF is enough for this application? Thank you for your help!

-Wenhao

over 6 years ago

0 Qian Chen over 6 years ago

TI__Mastermind 24075 points

Hi Wenhao,

How much output cap is used in customer's design?
If it is 3x10uF, it should be fine to use 10uF+2.2uF for VLDOIN cap.
Place 10uF+2.2uF close to VLDOIN pin in layout.

Thanks
Qian

0 Wenhao Wu over 6 years ago in reply to Qian Chen

TI__Genius 9046 points

Hi Qian,

If 10uF+2.2uF works fine when out cap is 3*10uF, what input cap will make it not fine? Could you explain more and clarify the rules? Thank you!

-Wenhao

0 Qian Chen over 6 years ago in reply to Wenhao Wu

TI__Mastermind 24075 points

Hi Wenhao,

It is just a recommendation.
10uF+2.2uF is close to half of 3x10uF, it should be fine.
With 3x10uF output cap, It may have problem if the VLDOIN cap is less than 10uF.

Thanks
Qian

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TPS51200: TPS51200 INPUT Capacitor