How to Use MCP4017T-103E/LT: Examples, Pinouts, and Specs

The MCP4017T-103E/LT is a digital potentiometer manufactured by Microchip Technology Inc. It features a resistance value of 10 kΩ and a 7-bit resolution, allowing for 128 discrete resistance steps. This component is controlled via a simple 2-wire I2C interface, making it ideal for applications requiring precise, adjustable resistance in a compact and efficient form factor.

• Volume control in audio systems
• Adjustable gain in amplifiers
• Calibration and tuning in sensor circuits
• LED dimming and brightness control
• Programmable power supplies and voltage dividers

The following table outlines the key technical details of the MCP4017T-103E/LT:

The MCP4017T-103E/LT is housed in a 6-pin SOT-23 package. The pin configuration is as follows:

1. Power Supply: Connect the VDD pin to a power source (1.8V to 5.5V) and the VSS pin to ground.
2. I2C Communication: Connect the SCL and SDA pins to the corresponding I2C lines of your microcontroller. Use pull-up resistors (typically 4.7 kΩ) on both lines.
3. Potentiometer Terminals: Connect PW0 and PW1 to the circuit where adjustable resistance is required. The wiper position is controlled via I2C commands.
4. Programming the Wiper: Use I2C commands to set the wiper position. The wiper position determines the resistance between PW0 and PW1.

• Ensure the supply voltage (VDD) is within the specified range (1.8V to 5.5V).
• Avoid exceeding the maximum wiper current of ±1 mA to prevent damage to the device.
• Use appropriate pull-up resistors on the I2C lines to ensure reliable communication.
• The device operates in a single-supply configuration, so ensure all voltage levels are referenced to VSS.

Below is an example of how to control the MCP4017T-103E/LT using an Arduino UNO:

#include <Wire.h> // Include the Wire library for I2C communication

#define MCP4017_ADDRESS 0x2E // Replace with the correct I2C address of your device

void setup() {
  Wire.begin(); // Initialize I2C communication
  Serial.begin(9600); // Initialize serial communication for debugging
}

void loop() {
  setWiperPosition(64); // Set the wiper to the midpoint (64 out of 128 steps)
  delay(1000); // Wait for 1 second
  setWiperPosition(0); // Set the wiper to the minimum position
  delay(1000); // Wait for 1 second
}

// Function to set the wiper position
void setWiperPosition(uint8_t position) {
  if (position > 127) {
    position = 127; // Limit the position to the maximum value (7-bit resolution)
  }
  
  Wire.beginTransmission(MCP4017_ADDRESS); // Start communication with the device
  Wire.write(position); // Send the wiper position (0 to 127)
  Wire.endTransmission(); // End communication
  
  Serial.print("Wiper position set to: ");
  Serial.println(position); // Print the position for debugging
}

1. No Response from the Device

   • Cause: Incorrect I2C address or wiring.
   • Solution: Verify the I2C address of the MCP4017T-103E/LT and ensure proper connections for SCL and SDA.

2. Erratic Behavior or Communication Errors

   • Cause: Missing or incorrect pull-up resistors on the I2C lines.
   • Solution: Add 4.7 kΩ pull-up resistors to both SCL and SDA lines.

3. Wiper Position Not Changing

   • Cause: Exceeding the maximum wiper current or incorrect I2C commands.
   • Solution: Ensure the wiper current is within the ±1 mA limit and verify the I2C commands being sent.

4. Device Overheating

   • Cause: Excessive current through the potentiometer terminals.
   • Solution: Limit the current through PW0 and PW1 to safe levels.

Q1: Can the MCP4017T-103E/LT be used with a 3.3V microcontroller?
A1: Yes, the MCP4017T-103E/LT operates with a supply voltage range of 1.8V to 5.5V, making it compatible with 3.3V systems.

Q2: How precise is the resistance adjustment?
A2: The MCP4017T-103E/LT has a 7-bit resolution, providing 128 discrete resistance steps.

Q3: What happens if the power supply is interrupted?
A3: The wiper position will reset to its default state. Ensure your system can handle this behavior if power interruptions occur.

Q4: Can I use the MCP4017T-103E/LT for high-power applications?
A4: No, the device is designed for low-power applications with a maximum wiper current of ±1 mA.