TPS54331 low dropout

Erin Zhang

Other Parts Discussed in Thread: TPS54331, TPS62090

Hi,

I want to add extra load but how much resistance load do I need to improve the low dropout of the TPS54331?

In case of Vin=5V and Vout=3.8V and no load ,the output voltage keeps changing. I wonder how much load do I need to keep the output voltage stable at 3.8V.

Thanks

over 8 years ago

0 Anthony Lang over 8 years ago

TI__Expert 4875 points

Hi Erin,

Could you share your schematic for us to review?

Best,
Anthony

0 Erin Zhang over 8 years ago in reply to Anthony Lang

Prodigy 130 points

Thanks and best regards~

0 Vental Mao over 8 years ago in reply to Erin Zhang

TI__Expert 5745 points

Please disconnect the R973 to see the Vout, it seems that the Cout is too big and the part is repeating start-up, also the loop may be not stable.

If removing the R973 is useless, please use the WEBENCH to choose the right value of these components, the L is a little big for 5Vin.

If you want to add a big Cout, please decrease the L and increase the Cap in the SS pin, also change the components in the Comp pin.

0 Chris Glaser over 8 years ago

TI__Guru**** 150620 points

The TPS54331 supports 28Vin. Why is it used for a 5Vin rail?

The TPS62090/85 are much better solutions for a 5Vin to 3.8Vout ay 3A rail.

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TPS54331 low dropout