The MCP3551DM-PCTL is a MCP3551 delta sigma ADC demo board designed to demonstrate MCP3551 22bit delta sigma analog to digital (ADC) converter performance using dataView software installed on a PC. The demo board can be used with MPLAB ICD2, PICkit 1 Flash Starter Kit, or PICkit 2 for developing demonstration/evaluation firmware. Optionally, a second installed MCP3551 can be used with and optional stimulus board. The board is designed to evaluate the MCP3551 with minimum printed circuit board (PCB) noise. The PCB layout practices low noise design to reduce the signal noise as much as possible in order to demonstrate the 22bit performance of the MCP3551. The circuit uses a ratiometric sensor configuration and uses the system power supply as the voltage reference. The extreme common mode rejection capability of the MCP3551 device, along with it's excellent normal mode power supply rejection at 50Hz and 60Hz, allows for this system performance.