TPS72515

Hello Jessie,

Please send us a schematic and any details about circuit environment.  And if this is becoming immediately critical, contact your local sales/applications support to help with the Failure Analysis proceedures.

Bill

Hi Bill,

Thanks for your quick answer. The schematic is rather simple, as the TPS72515 (U29) has an input capacitor (C83 1uF/10V/Ceramic) and an output cap (C84 22uF/6V3/Ceramic). The Enable and In pins are tied together and directly connected to the 3.3V from a PCI slot. The reset pin is unused. The 1.5V output is only used to feed an onboard CPU's VCore, so some decoupling 100pF, 1nF and 10nF are spread around the CPU itself. For obvious reasons, there is also caps between the different voltages as shown on the schematic excerpt below.

Hope this helps.

Hello Jessie,

This looks good. You are right, these are simple circuits. 

We would like to start the Failure Analysis (FA) process.  Fill out the attached document as best you can, and then send it to us with a few bad parts. Or if possilble contact your local TI applications support so that we can arrange a phone conversation (and let him fill out the paper work).

The data sheet seems to indicate that the part is sensitive to noise and input capacitance - do you see any oscillations? Does the part get hot? With no load, does the part return to nominal 1.5V? Is this voltage tested during production? Have you duplicated the problem in the lab on a separate breadboard? What percentage are failing? Do failed parts act the same on another good board?

And yes, having asked these questions it could be that you have parts whose output programming is suspicious.  We had a report of this in 2007 for this part but it was not duplicated.

Regards

Bill