We have a problem with some 10% of boards that have a circuit featuring the TPS61260.
I think my question may boil down to possible ground connection issues.
I would also like to know what is the Max IFB for this part (not sure that this is actually specified on the data sheet) ?
I would welcome feedback from anyone who has had experience of using this part in a production environment, and in particular has undertaken re-work of if it in-situ ?
Although the particular board is not our design / layout, and they have been assembled by a contractor, having had a look at these there is nothing obviously wrong with the circuit / layout, or indeed the assembly of same.
Out of an initial (pre-production) batch of c 50 Pcs, we have 4 Pcs that have failed.
The input is 3.0V nom, with a 170K / 1M divider to give 3.5V nom output, and the max average output current set at 75mA nom (although typically only drawing 10mA max) with RI at 27K, (+ 4.7uH inductor, plenty of capacitance both input and output).
The good boards all put out 3.5V - as designed.
But for the bad boards the output is around only 1.6V. We tried changing the TPS61260 for a fresh one, and the output voltage then came up to 2.2V, (also tried isolating the output first - but didn't make much difference). I actually got one of our experienced production people to change the device, as it looked really difficult to re-work with the ground pad underneath the package ! For the 1.6V output I measured only around 0.2V on the feedback pin (wrt to the PCB ground plane). Does this suggest the problem we are seeing is with the ground connection of the device ?
Any thoughts or comments from anyone who has experienced similar issues ?
Thanks in advance.