The MCP41050-I/SN is a single 50kOhm 256-tap digital potentiometer from Microchip in SOIC-8 with SPI interface. The resistor string consists of 255 equal resistors connected in series between terminals PA and PB. The wiper (PW) connects to one of 256 nodes (0-255) via CMOS switches controlled by the 8-bit wiper register. The resistance between PW and PA is RWA = (256 – D) x RAB/256, and between PW and PB is RWB = D x RAB/256, where D is the wiper code (0-255) and RAB is the total resistance (50kOhm +/-20%). The SPI command format is a 16-bit word: 2 don’t care bits + 2 command bits + 4 address bits + 8 data bits. The wiper resistance (contact resistance of the CMOS switch) is typically 75Ohm, which limits accuracy at low wiper positions. The device can also be configured as a variable resistor (rheostat) by connecting only one terminal and the wiper. Power consumption is less than 1uA in standby. The -I suffix specifies industrial temperature range (-40C to +85C). Typical applications include LCD contrast adjustment, gain control, and voltage trimming in circuits where mechanical potentiometers would be impractical.