TPS54625: can't power up

user1566168

Prodigy 60 points

Part Number: TPS54625

see schematic below.

after power on,VOUT is 0.8V.
The wave shows Vin (blue 12V) shakes at rising edge.
Vout (yellow 2.5V) ends below 1V.

why tps54625 can't retry and get back to work normally?

over 7 years ago

0 Vental Mao over 7 years ago

TI__Expert 5745 points

Please upload your Layout, the schematic looks well.
And what's your load at the output when you power on?

0 user1566168 over 7 years ago in reply to Vental Mao

Prodigy 60 points

Hi Mao,

most times,it works well at 25℃.very seldom can not power up.
when below -30℃,always can not power up.
when below -40℃,can not power up for sure.

Even the input voltage(12V) vibrating at rising edge,tps54625 can not auto retry and get back to normal?

layout top:

layout all:

0 Vental Mao over 7 years ago in reply to user1566168

TI__Expert 5745 points

Do not connect SS to the PGND, change it to connect the GND on the top layer. And use the X7R cap for the all temp.
Can you upload the SS waveform? Make sure the SS cap solder down well.

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TPS54625: can't power up