Rev1 Results

With the first rev of PCBAs, I bought the raw PCBs and the components separately, and performed the assembly of the boards in-house, with mixed results.

 

I did all the soldering, starting with the SMD components with no-mess solder paste and a heat gun, and ending with the through-hole components. Note the red wire connecting from a 6-pin SMD package to a larger 8-pin SMD footprint in the PCB. This was because I had changed the NMOS component in my KiCAD schematic without updating the layout.

One of the main articles that didn’t work well on the first rev was the PVDD (18V) power switching circuit. When 3V3 was supplied to the gate of the NMOS FET, the intent was that V_sg of the PMOS FET would reach 18V, and allow current to flow from source to drain. When I switched on the gate, I only ever measured 0V between the PVDD net and GND. I didn’t get to debug why this was before the circuitboard failed due to a short circuit while debugging.