Microchip MCP4651-502E/ST: A 7-bit Dual Digital Potentiometer with Volatile Memory

The Microchip MCP4651-502E/ST is a highly integrated dual-channel digital potentiometer designed to provide a programmable resistance solution in a wide range of electronic applications. This device serves as a solid-state replacement for traditional mechanical potentiometers and trimmers, offering enhanced reliability, smaller form factor, and the convenience of digital control.

Functioning as a 7-bit volatile memory digital potentiometer, the MCP4651 features two independent potentiometer channels, each with 129 wiper positions (values from 0 to 128). The 7-bit resolution provides a fine adjustment capability for applications where precise control over resistance, voltage division, or current is required. Its volatile memory means the wiper position is not retained when power is removed; upon power-up, the wiper resets to a mid-scale value (typically 80h, or position 64). This makes it ideal for systems where the host microcontroller or processor must actively set and manage the desired operating point during initialization.

Communication with the device is achieved via a standard I²C serial interface, supporting both normal (100 kHz) and fast (400 kHz) mode operations. This allows for easy integration with a vast majority of microcontrollers, enabling simple digital control of resistance settings. The MCP4651-502E/ST variant offers a nominal end-to-end resistance of 5 kΩ.

A key feature of this digital pot is its dual potentiometer configuration in a single package. This design saves valuable board space and simplifies design by providing two matched and tracking resistive elements. Each potentiometer can be used independently for dual-channel applications like stereo audio volume control or differential circuit tuning, or they can be used in tandem for more complex requirements.

Typical applications are extensive, spanning from industrial control and automotive systems to consumer electronics. It is commonly used for system calibration, parameter adjustment, sensor trimming, offset and gain control in op-amp circuits, and as a programmable voltage reference.

ICGOODFIND: The MCP4651-502E/ST from Microchip is a versatile and space-efficient solution for digital resistance control. Its dual-channel 7-bit architecture with volatile memory and I²C interface provides designers with a reliable and digitally controllable component, perfectly suited for applications where settings are dynamically managed by a host processor and where board space is at a premium.

Keywords: Digital Potentiometer, I²C Interface, Volatile Memory, Dual Channel, 7-bit Resolution