TPS795: tps79518/33

Hi Deepak,

Thanks for providing the schematic. In order for us to help identify the issues, will you be able to provide more details on what do you mean by "it burns" and what exactly happened? Please also include scopeshot on Vin and Vout and if you have any load, please also include the output and input current in the scopeshot. 

Regards,
Jason Song

Dear Jason

I am not using any load, the circuit is just connected to the supply( APLAB, regulated DC supply) 5 V. Once or twice I got the outputs, but then output of say 3.3 or 1.8 is not coming and the input and ground show short circuit( that's what I meant burns, not the actual smoking).

I have destroyed almost 6 ics . 

Hi Deepak,

Here are the things I would suggest you to check on your baords.

1. Without the device on the board, will you check all the continuity to the pins to see if there are any shorts on board.

2. After you solder the device on PCB, before providing any power do the check again and make sure there are no shorts caused by soldering.

3. Another things you should do is to limit the current of the supply, if you don't have any load on the output, try to limit the current of the supply to the input pin. Startying from a few mili-amps, and see if it gets clamped. At no load, the typical current the device is sinking should be somewhere close to the ground pin current, you may refer to the datasheet to find out the value.

4. If problems persists, instead of trying addtional parts, before powering on the device, connect scope prob to input pin, output pin, fb pin and a current prob on the output pin as well. Please take a scope shot and share it to use. In most of the cases, a scope shot can help quickly identify the issue. 

Please let me know this solves your issue or you still have problem.

Regards,
Jason