Skip to main content


This article describes the CHESTER-X4 extension module.

Module Overview

CHESTER-X4 implements a step-down DC/DC converter providing power from an external 6-28 VDC line (VIN). It allows also the input voltage measurement. This module has also 4 P-MOS switches allowing to supply of independent loads from VIN voltage input.

Output Protection

Each of the four outputs has a resetable PTC fuse protection (femtoSMDC005F). Each output can reliably supply 50 mA of constant current. The trip current is around 150 mA.

CHESTER Pin Configuration Diagram

Pin Configuration and Functions

PositionSignal NameSignal Description
1GNDSystem ground signal
2CH1Channel 1 voltage output switch
3CH2Channel 2 voltage output switch
4CH3Channel 3 voltage output switch
5CH4Channel 3 voltage output switch
6GNDSystem ground signal
7GNDSystem ground signal
8VINDC power supply voltage input (6-28V)

Schematic diagram

A schematic diagram is useful if you program low-level hardware-related code or if you're just curious about how the system is designed.

Module Drawing