I am building an impee that reads a thermocouple and I’ve copied the power control part of the April design for my board. My board uses the same TPS62172 buck converter to step the 5V input voltage down to 3.3V. Unfortunately, I am only getting 0.5V out of the buck converter. This is my first SMD board so my problem could be related to my design or my soldering of the tiny 2mm square component.
If anyone has ideas about potential problems to check for I would appreciate them. At this point I’ve done a lot of hot air rework on the board and replaced the buck converter (which brought the voltage from 0V to 0.5V).
Bucks tend to be very layout critical. Did you copy the layout from the April too?
Soldering may also be a problem. The best idea with small components like this is to put loads of flux on there and then reflow the component with hot air; if you put it on slightly skew, you should see it snap into line as the solder melts.
I did change the board layout a bit, so that may be part of the problem, however my bad soldering seems more likely. I was attempting to melt more soldering paste with my hot air rework, I’ll try tinning the chip leads and the pads then coat both with flux. The input voltage seems fine when the output is low. It’s just so odd that my output voltage is 0.5V, I’d expect it to be 0V if I mis-soldered something.