TPS60403: Constraints on 5V Supply?

Ian Murray11

Part Number: TPS60403
Other Parts Discussed in Thread: LM27761

Hi there,

I have a design using a TPS60403 inverter to supply a TPS72301 as follows:

It works as intended when its +5V input comes from a linear regulator, but when a switching regulator such as the LM2596S (or a benchtop DC supply) is used to provide this input, the TPS60403 seems to overheat.

Is there some frequency interference going on? Or some other constraint I can't find in the data sheet? Any recommendations for getting it to function with a switching regulator?

Thanks,

Ian

over 6 years ago

0 Clemens Ladisch over 6 years ago

Guru 316470 points

Charge pumps draw a very noisy current from their input. Try increasing C36.

0 Chris Glaser over 6 years ago

TI__Guru**** 150690 points

Hi Ian,

Can you share your PCB layout and BOM for the caps around the TPS60403?

We also have the LM27761, which has the LDO built in.

0 Chris Glaser over 6 years ago in reply to Chris Glaser

TI__Guru**** 150690 points

Hi Ian,

Were you able to find a solution or would you like some assistance?

0 Ian Murray11 over 6 years ago in reply to Chris Glaser

Intellectual 310 points

I'm going to mark this as resolved since I verified that the principle source of noise seemed to be a coupling issue on the layout! Thanks for the help.

0 Chris Glaser over 6 years ago in reply to Ian Murray11

TI__Guru**** 150690 points

Thanks for sharing your findings!

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TPS60403: Constraints on 5V Supply?