Hi,
We have been using TPS62290DRVT as a power stage component in our design to derive 1.8V output delivering 25mA(during normal operation) from 5V power input via USB 3.0 connection. The design has been released for production & in the first batch of production boards we have two cases of Bad boards running hot and measuring very low impedance(16 Ohms and 55 Ohms) between SW node and GND of the board.However, We did not any shorts or low impedance between other pins (except GND) to GND or Vin to SW.
Both the bad boards output nearly 1.9V output instead of nominal 1.8V. We had probed the SW node w.r.to GND in the Bad boards & good board(working one) & we have attached the screenshots for your reference.
Our design is a USB powered product & VBUS from USB is provided to VIN of the TPS62290. We have attached the snapshots of power section of our design and the layout of TPS62290DRVT for your reference.
We did go through several other tickets in the TI community describing similar issues in the different part no. but we are unable zero in to the exact cause of this issue.
It is to be noted that during the proto-design stage we have put several units for long run test and had gone through lot of plugging/un-plugging as this is a USB powered product. Despite all this we did not find the regulator running hot.
We have seen just two cases but we are not sure whether this is could be a latent issue in rest of the boards in the batch.
Kindly take this as priority & let us know on this ASAP. At present, We are half way into the process of the next batch of production.
Balaji