TPS62740 dying for no apparent reason.

Trashaccount1912

Other Parts Discussed in Thread: TPS62740

Hi everyone,

I am using a TPS62740 as a supply for an MSP430 and some peripherals. The current consumption is at no time greater than 100mA so there should be no problem. Vin comes from a LiIon battery, so that should be alright, too. Vout is just as configured, and everything seems to be ok, yet it sometimes just dies without any visible reason.

So what kind of things should I look into to get this thing to work reliably? Thanks a lot in advance,

Andreas

over 10 years ago

0 Florian Feckl over 10 years ago

TI__Expert 7110 points

One very important part is the PCB layout of your power solution. It is very critical in terms of component placement and routing. Can you post a cut-out of the layout as well?

0 Trashaccount1912 over 10 years ago in reply to Florian Feckl

Prodigy 150 points

Hi Florian,

I hope these shots are good enough, if not let me know.

0 Florian Feckl over 10 years ago in reply to Trashaccount1912

TI__Expert 7110 points

Thanks for the shots.
Basically, It is hard to judge why you see IC's getting damaged. For debugging your circuit it helps a lot to check traces like VIN, VOUT, SW-Node close to the device with a high-impedance probe.

The layout can add series impedance's that let the power generate spikes which can damage the IC.
Your routing has a quite long GND Loop on input and especially at output. Please have a look at the datasheet, page 23 where a recommendation is listed. I'd definitely recommend to follow this example and use planes for a low impedance connection.

Power management

Power management forum

TPS62740 dying for no apparent reason.