A lot of circuits need a positive and a negative supply rail, so I created a simple USB dongle that gives me arount +/- 5V (unregulated) from a USB port. Output is through a 4-pin audio jack. There's a secondary inlet that allows to connect a 2S LiPo or LiIon battery to be use through the balance lead.
The original PCB's cutout was too small for the DCDC converter. I fixed that and ordered new PCBs from PCBWay with 2 mm thickness for a better fit in the USB slot.
Here's a picture:
The copper geometry and ENIG finish look good! Solder mask is very well aligned with the pads, and silkscreen placement is not perfect but good enough.
It also fits very well in a USB slot, much better than 1.6 mm and with less chance of just falling out.
I just made a mistake myself: I had to order a couple more DCDC converters because I had only one left, but the type I used previously was sold out - and the replacements I ordered have a different pin geometry. That could be fixed with a little bending, but it's ugly: