Went ahead and punched out the production PCB order (quantity 210).
Here’s the new design:
And the layers:
Major changes from the prototype are:
- Bigger holes for the wires and shield – those on the prototypes were too tight. Also went to .150 traces for better current and thermal capacity by abandoning any attempt to be pretty.
- Re-aranged diodes D1 / D2 from the end of the board to the middle so that they will fit entirely within the enclosure without modifying it.
- Added a through-hole flyback diode and discharge resistor, in addition to the SMD pads. At 1K the SMD discharge resistor was getting a little warm for my liking.
- Enlarged thermal planes with additional thermal vias – the diodes got way hotter than I was expecting.
Vector art here: skbowe_2.0.4_art.pdf
ExpressPCB design file here: skbowe_2.0.4.pcb