Debug Board USB to RS232 Isolated Serial Converter

What is it?

  • This is a USB to UART converter with a digital isolator on the RS232 side

Why did you make it?

  • I was using a cheap USB serial converter, but sometimes they didn’t work correctly and I was losing time.
  • So we decided to design our own customized board, with only the essential pins and the possibility to work at 1.8V.
  • With the galvanic isolation and the possibility to work at different logic levels according to the target voltage.

What makes it special?

Thanks to the digital isolator MAX12931BASA+ the computer and your target board are electrically isolated.

  • The noise coming from your computer doesn’t enter in your target board, this can be useful when you are working with sensible analog circuit.
  • The voltage levels of TX and RX are the same of your target board. This means that it doesn’t matter if your board is working at 5V or 3.3V or 1.8V, the logic level are always correct!

Technical data

  • Original FTDI FT230X: Compatible with almost all the operating systems and capable of variety baud rates of 300 baud to 3 Mbaud
  • Size of 40 x 13mm.
  • 4mm isolation between the two sides guarantee an electrical isolation up to 1kV
  • Working at 1.8V up to 5V.
  • Tested in a climatic chamber from -20°C up to 80°C
  • TX and RX LEDs indicators.
  • Micro USB connector.
  • Standard 2.54mm 4 pins female header.
  • Protected by a transparent heat shrink sleeve.


NameDescriptionDirectionVoltage level
+Power SupplyInput1.8 - 5V
TXTransmitted DataOutputSame of +
RXReceived DataInputSame of +

Check out our experiment with the main power supply: 

Eye diagram at 3Mbaud power supply: 1.8V

Eye diagram at 3Mbaud power supply: 5V

You can purchase this item in our Tindie and eBay stores: