TMS320VC5509A: Problem with TMS320VC5509A shorting 3.3V supply

Hi,

6 to 10% of chips fail over from 2 months to 5 year period.

Can you elaborate a little here? Do you mean that when you produce your boards 6 to 10% get damaged in the first couple of months??

If yes, can you verify your design comply with device Data Manual and the bellow hardware design guides:
www.ti.com/.../sprab14.pdf
www.ti.com/.../spraa30.pdf
www.ti.com/.../slva206.pdf

Also have you performed PDN analysis & SI analysis of your design?

Best Regards,
Yordan

Also have you checked your pcb design?

In other words, I am asking if you've verified that you don't have a mistake in your schematics or pcb?

Best Regards,
Yordan

Thanks for the pointers - Will look into.  

One of my questions am looking into is about unexternally terminated inputs (like A/D lines) however do not know if it leads to excessive current or slightly higher current.

Hi Chris
There is not enough debug / failure information in this post for us to offer any help.
Please explain your failure modes and debug done so far.
Have you isolated the issue to be device or board related i.e. have you done ABA swaps.

If you think you have faulty devices, you can follow the guidelines listed in the following page
www.ti.com/.../customer_returns.page
to return some failing units for failure analysis (recommend going through the guidelines listed on the page).

"One of my questions am looking into is about unexternally terminated inputs (like A/D lines) however do not know if it leads to excessive current or slightly higher current"

Any floating IOs can have board to board / device to device variability that can cause more than expected current - is more than expected current draw what you are calling as "failing"?

I don't know if something specifically exists for c5509a, but you can also look at the following application note (Section 4 and 5)
www.ti.com/.../sprac07.pdf


Regards
Mukul