UCD3138: UCD3138RJAR DPWM OUTPUT HIGH DURING V33D START-UP

jun yin

Part Number: UCD3138

Hi Sir:

We are using UCD3138RJAR to replace old UCD3138RHAR, while we found this issue during test; at high temperature, like 70'c, we saw DPWM output high following V33D during start-up, waveform is attached;

CH1:V33D, CH2:DPWM0B

after that, the UCD3138RJAR could work normally; when we use old UCD3138RHAR, we didn't see this issue;

so what happened to UCD3138RJAR

the top mark for this lot of UCD3138RJAR is 6BJ P1JF G4

over 6 years ago

0 Brian Johnson96 over 6 years ago

TI__Expert 3200 points

Hi Jun,

An AE should be helping on your question soon.

0 Sean Xu over 6 years ago

TI__Genius 13570 points

Hi, Sean,

As you said, you don't have cap between V33D and BP18. The cap is needed to remove the pulse during start up. Please refer to the D/S for more detail.

Regards,
Sean

0 jun yin over 6 years ago in reply to Sean Xu

Intellectual 875 points

thanks a lot Sean, and thanks big boss;

Power management

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UCD3138: UCD3138RJAR DPWM OUTPUT HIGH DURING V33D START-UP