Part Number:TPS548B22
Hi Team,
Recently, we built a board using the TPS548B22 as a regulator to take a 12V supply down to 1.1V. In a recent revision, we attempted to move the RSP line to the load location rather than directly after the output of the TPS548B22. During this update, we neglected to move the VOSNS line, which is still shorted to the output of the regulator. Between the TPS548B22 output and our load, we have a current shunt monitor (INA250A1) to sense the current on the supply rail, so RSP is connected after the shunt monitor output, while VOSNS remains between the regulator output and current shunt monitor input.
We are currently observing that the 1.1V regulator output does not come up unless we blue-wire to short RSP and VOSNS together at the output of the regulator so that they share the V1P1 net, rather than RSP connecting to V1P1_0 (after current shunt monitor) and VOSNS connecting to V1P1 (before current shunt monitor). Is there a mechanism in the TPS548B22 that could be preventing the 1.1V regulator output in this configuration? The current shunt monitor should only be presenting approximately 0.1-Ohm resistance, i.e. virtually the same voltage.
Any thoughts or explanation about the behavior we're seeing would be helpful as we debug!
Thanks,
Michael