AD8310 module for HF current probe

This article documents the RF electronic part of a HF current probe project.

The AD8310 module was bought on eBay for about $10.

The module as supplied had a 100Ω resistor in shunt with the input, it needs to be 52.3Ω 1% 0805 resistor for a good match and was replaced with such.

I want to run this from a 3.7-5V supply so the on board 5V regulator was replaced with a NJM78L03UA 3V regulator (which has the SOT88 package with the same pinout as the original). The regulator chip is a little skewed as a result of poor solder mask layout and solder surface tension… but it will work fine.

Above is a sweep with a (modified) nanovna-H to 100MHz (this is for a HF current probe). Input VSWR would be more like 2 as supplied with the 100Ω input resistor… Chinese Quality.