Microchip MCP4011T-503E/MS Digital Potentiometer: Features and Application Circuit Design

The Microchip MCP4011T-503E/MS is a 7-bit digital potentiometer designed to provide a compact, solid-state replacement for traditional mechanical potentiometers. As a member of the MCP40D1X series, this device offers non-volatile memory (EEPROM), allowing it to retain its last wiper position even after a power cycle. This feature is particularly advantageous in applications requiring preset configurations upon startup. With a resistance value of 50 kΩ and offered in a space-saving MSOP-8 package, it is well-suited for modern, high-density PCB designs.

Key Features of the MCP4011T-503E/MS:

- 7-Bit Resolution: Providing 128 wiper steps for precise adjustments.

- 50 kΩ End-to-End Resistance: Suitable for a wide range of analog signal conditioning tasks.

- Non-Volatile Wiper Storage: The wiper setting is saved in EEPROM, ensuring reliability across power cycles.

- Simple I²C-Compatible Interface: Allows easy control with a wide variety of microcontrollers.

- Low Power Consumption: Ideal for battery-powered and portable devices.

- Extended Temperature Range: Operates from -40°C to +125°C, making it robust for industrial environments.

Application Circuit Design:

A typical application circuit for the MCP4011T-503E/MS involves using it as a programmable gain controller for an operational amplifier (op-amp). Below is a basic example of a non-inverting amplifier with adjustable gain:

1. Components Required:

- Microcontroller (e.g., PIC, Arduino)

- MCP4011T-503E/MS

- Op-amp (e.g., MCP6001)

- Resistors (for biasing, if needed)

- Power supply (2.7V to 5.5V)

2. Circuit Configuration:

- Connect the VDD pin (Pin 1) to the positive supply (e.g., 3.3V or 5V) and VSS (Pin 4) to ground.

- The A (Pin 6) and B (Pin 7) terminals of the potentiometer are connected across the feedback path of the op-amp. Terminal A is connected to the output of the op-amp, while Terminal B is connected to the inverting input.

- The Wiper (W) (Pin 5) is connected to the inverting input of the op-amp, effectively creating a variable feedback resistor.

- The I²C interface consists of SCL (Serial Clock, Pin 2) and SDA (Serial Data, Pin 3), which are connected to the corresponding pins on the microcontroller. Pull-up resistors (typically 10 kΩ) are used on both SCL and SDA lines to ensure proper communication.

3. Gain Calculation:

The gain of the non-inverting amplifier is given by:

\[

Gain = 1 + \frac{R_{AB}}{R_{BW}}

\]

where \( R_{AB} \) is the total resistance (50 kΩ) between A and B, and \( R_{BW} \) is the resistance between B and the wiper. Since the wiper position is digitally controlled, the gain can be programmed dynamically by sending appropriate commands via the I²C interface.

4. Software Control:

The microcontroller sends I²C commands to set the wiper position. For instance, to set the wiper to the mid-scale (position 64 out of 127), the corresponding byte is transmitted. The EEPROM ensures this setting is maintained after power-down.

This circuit demonstrates how the MCP4011T-503E/MS can be used to create a digitally controlled analog system, eliminating the need for manual adjustment and enabling remote or automated calibration.

ICGOODFIND: The MCP4011T-503E/MS digital potentiometer from Microchip is an excellent solution for applications requiring reliable, programmable resistance. Its integration of EEPROM memory, simple digital interface, and compact form factor make it ideal for use in audio equipment, sensor calibration, power supply regulation, and automated test systems. By replacing mechanical pots, it enhances system durability, precision, and automation capabilities.

Keywords: Digital Potentiometer, Non-Volatile Memory, I²C Interface, Programmable Gain, Signal Conditioning.