This is a continuation of a thread I started
here.
The first board I built was too wide (for a standard breadboard) so I shrunk the width, it's now 36 x 21.5 mm. I also did away with the PTC as it dumped power whenever any load was drawn.
What I ended up with is a CY7C65213A USB-serial adapter, which includes a small power supply (components under the PCB). It is plug and play with many operating systems and enables serial communications with low voltage PCBs using RS232 (ground referenced) voltages as low as 1.7V The power supply section offers 3 (shared ground) supplies of 5V, 3.3V, and 1.7V – 4.2V adjustable. It's built and tested and I have several spare PCBs.
The small FT232 PCBs that you can get for $5 are OK but they:
a. Can only be used at 5V or 3.3V levels
b. Have very limited power output capability (if any)
c. The really cheap ones from Banggood and Aliexpress have fake FTDI chips on them which can mess up your communications
Design files are in the next post and there's a couple of pictures below.