What is it?

olmBoard is a small and a breadboard-friendly, ultra-low-power buck converter module with TPS62840 step-down converter at its heart.

Check out this excellent review from @Voltlog on his YouTube channel.

TPS62840 is an ultra-low-power switching regulator from Texas Instruments. It offers super low operating quiescent current (IQ) at 60 nA, and delivers very high light-load efficiency of 80% at 1-µA load.

The TPS62840 IC provides an output current of up to 750 mA. With the input voltage from 1.8 V to 6.5 V, the device supports multiple power sources such as 2S to 4S alkaline, 1S to 2S Li-MnO2, and 1S Li-Ion/Li-Po/Li-SoCl2. JST-PH connector has also been added for easy battery connections.

Some specs:

• Operating quiescent current: 60 nA
• 100% duty-cycle mode with 150 nA IQ
• Input voltage range (VIN): 1.8 V to 6.5 V
• Output current: up to 750 mA
• RF-friendly DCS-control
• 80% efficiency at 1 µA IOUT (3.6 VIN to 1.8 VOUT)
• 16 selectable output voltages via VSET pin
• Auto-transition PFM/PWM or forced-PWM mode
• Selectable forced PWM and STOP modes
• Output discharge (OD) function
• Shutdown current: 20 nA
• Output: by default it's set to 3.3V but it can be changed easily with a solder jumper (predefined jumper pads).
• Module dimensions: 15.2 mm x 31.1 mm (0.6 in. x 1.225 in.)

Initial sweep load test results w/ 0.1A at 10 sec increments using EBD-USB load tester is shown below. The module works well up to 1A loads (short term), and recommended max. output current is 750mA. Voltage drop in the graph is due to the USB cable drop, actual voltage is stable around 3.3V up to 1A loads.

Why did you make it?

I needed a ULP buck converter module for my Penguino Feather board and this IC sounded very promising. I decided to give it a try and build a small module to test it out.

What makes it special?

This IC offers some unique features and it's one of the lowest operating current buck converters I've ever seen. Additinally it has a selectable output voltages (default 3.3V) with solder-jumper selectable ranges from 1.8V to 3.3V.