LMR54410: ripple in output when power up

Chi Zhang2

Part Number: LMR54410

Hi Expert,

My customer is using LMR54410FDBVR, but find abnormal ripple when power up.

24V input to 15V output, ripple time is 30us, please help to give some suggestion

here is the output wave; green one is output, yellow one is input.

here is the schematic

0 Jimmy Hua 2 months ago

Hello,

Can you let me know which orderable part number is stuffed on the PCB?

Also in this waveform is the it at no load or full load 1A?

Regards,

Jimmy

0 Chi Zhang2 2 months ago in reply to Jimmy Hua

Hi Jimmy,

the orderable part number is LMR54410FDBVR. it is for no load.

Chi

0 Jimmy Hua 2 months ago in reply to Chi Zhang2

Hello Chi,

Please also get a waveform scopeshot of both the SW node.

Since it is a FPWM (fixed frequency) device, I am expecting the SW node to be a fixed square and cyclical.

However if when the device completes soft-start and VOUT regulates, I want to see if SW is steady or changing.

That would give me an idea of why there is ripple.

Regards,

Jimmy

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