TPS23756: Vds voltage spike goes to 150V

chentsu chung

Mastermind 6180 points

Part Number: TPS23756
Other Parts Discussed in Thread: PMP40514

Hi Team,

After our customer combine the cap C14/C16/C17 to one 100uF, than they found device damaged.

And they found voltage different at:

Point A: voltage spike goes to 152V

Point B: Voltage spike goes to 30V

Please help to check what can make this damage?

Thank you

C.T.

over 4 years ago

0 Michael Pahl over 4 years ago

TI__Mastermind 21320 points

Hello C.T.,

Thank you for your question. The high voltage on VC looks to exceed the maximum voltage rating for that pin, which is probably what is damaging the device.

To confirm, the customer did not change anything except the values of C14,C16,C17 to be equivalent of 100uF?

Was this done on the PMP40514 board, or did the customer create their own layout?

Regards,

Michael Pahl

0 chentsu chung over 4 years ago in reply to Michael Pahl

Mastermind 6180 points

Hi Michael,

Yes, the damage happened after change the caps, and it's done on their own board.

Thank you,

C.T.

0 Michael Pahl over 4 years ago in reply to chentsu chung

TI__Mastermind 21320 points

Hello C.T.,

Can you send me a copy of the customer schematic?

This might be a stability problem because the loop is designed for a specific output cap, but I want to look at the schematic first.

Regards,

Michael Pahl

0 Michael Pahl over 4 years ago in reply to Michael Pahl

TI__Mastermind 21320 points

Hello,

We have not heard anything from you end in almost a week. I will consider this thread solved if I do not hear from you in 48 hours. You are always welcome to post here if the issue is on going, or create a new post if a new issue arises.

Thank you for your interest in TI PoE products.

Regards,

Michael Pahl

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TPS23756: Vds voltage spike goes to 150V