SN65HVS881: SN65HVS881 internal LDO is broken, 5VOP pin short circuit to GND.

Eggsy Pang

Expert 4985 points

Part Number: SN65HVS881

Hi team,

My customer use many pcs SN65HVS881 in their I/O board.

it have production. But they found SN65HVS881 5VOP pin short circuit to GND, which often happen. Below is their SCH.

Do you have any suggestions?

Thanks!

over 6 years ago

0 Helen Sun over 6 years ago

TI__Intellectual 2355 points

Hi Eggsy,

What is the setup conditions when the short to ground fault occurs on 5VOP? the 5VOP pin is a 5V output to supply low power isolators. In your schematics is seems like there is a 5V supply to 5VOP. Could you please clarify?

thank you,

Helen

0 Eggsy Pang over 6 years ago in reply to Helen Sun

TI__Expert 4985 points

Hi Helen,

Thanks for your help!
No any special conditions , just working in their product and sometimes it is broken.
Could you see the R155 in SCH, which is DNP and meaning there are no 5V supply to 5VOP.
Do you have any suggestion? May it be Over input voltage?
Thanks!

0 Helen Sun over 6 years ago in reply to Eggsy Pang

TI__Intellectual 2355 points

Hi Eggsy,
What is the failure rate observed, meaning how many parts failed out of how many parts tested? Is the failure symptom always the same that 5VOP is short to GND?
There could be some transient on the damaged pin that could cause a short. Is there waveform captured for your production test?
thank you.
Helen

0 Eggsy Pang over 6 years ago in reply to Helen Sun

TI__Expert 4985 points

Hi Helen,

It is failure in product rather than test. 10% parts are failure. Failure symptom is always the same that 5VOP is short to GND.
It is hard to capture the waveform. Do you know what kinds of transient would damage pin? And how to protect it?
Thanks

0 Adam Torma over 6 years ago in reply to Eggsy Pang

TI__Mastermind 45575 points

Eggsy,

I will be taking over support for Helen. Is this issue still open? Do you have any additional updates or new questions after your investigation?

Thank you,

Adam

0 Eggsy Pang over 6 years ago in reply to Adam Torma

TI__Expert 4985 points

Hi Adam,

Thanks for your help!

Do you know what kinds of transient would damage pin? And how to protect it?

0 Adam Torma over 6 years ago in reply to Eggsy Pang

TI__Mastermind 45575 points

Eggsy,

Without seeing more information on your waveforms I can only speculate any transients that are outside the recommended operating conditions. Many customers use clamping diodes limit the voltage and series resistors to limit the current.

Thank you,

Adam

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SN65HVS881: SN65HVS881 internal LDO is broken, 5VOP pin short circuit to GND.