This is a small power supply for the RF filter block project.

It takes a single 18650 cell and outputs a regulated 3.0V supply. The board also contains a cell protector.

The protection IC is a BQ29700DSER that will disconnect the cell if it’s charged over 4.275V or over-discharged under 2.800V.

The protected cell output is available on the two connection posts for easy charging

The schematic is simple – the datasheet application for the protection IC + the 3.0V LDO: 1s_board.pdf

As usual, the entire project is available on github:18650_1s_board

The board is a simple 2 layer layout:

The parts are quite close to the 18650 connector and there is a pair of 3mm mounting holes:

The assembled board worked form the first try, but it needs a low current “power” led.

The battery is a very nice fit: