What is it?

UPDATED (2022/02/07) - these are back in stock! One caveat is that the 4 position switch is actually 12 positions, but will repeat through the 4 positions 3 times.

This is a REF200 low current reference.

The REF200 combines three circuit building-blocks on a single monolithic chip: two 100-μA current sources and a current mirror. The sections are dielectrically isolated, making them completely independent. The performance of each section is individually measured and laser-trimmed to achieve high accuracy.

This module provides currents of 100 μA, 200 μA, 300 μA, or 400 μA.

Why did you make it?

I needed a low current reference to verify my test equipment for IoT projects and low current test. I found Scullcom Hobby Electronics video on the REF200 and transferred the project to some PCBs.

It's cheaper to order things in bulk, so I have a number of these on hand after making the one that I really wanted.

What makes it special?

This module provides currents of 100 μA, 200 μA, 300 μA, or 400 μA via a USB connection.

You can provide power to it via a USB connection to your computer or through a battery. Your choice!

It's ready to be put into your own project box. The terminal connectors are screwed on so jumpers can be run from your project box to the PCB.