How to Use MCP 4735: Examples, Pinouts, and Specs

The MCP4735 is a low-power, single-channel digital-to-analog converter (DAC) manufactured by Arduino. It is designed to convert digital signals into precise analog voltage outputs, making it an essential component in applications requiring fine voltage control. With a 10-bit resolution and an I2C interface, the MCP4735 is ideal for use in audio systems, sensor interfacing, and other applications where accurate analog signal generation is required.

• Audio signal processing
• Sensor calibration and interfacing
• Voltage reference generation
• Precision control systems
• Industrial automation

The MCP4735 is a versatile DAC with the following key technical details:

The MCP4735 comes in a 6-pin SOT-23 package. Below is the pinout and description:

The MCP4735 is straightforward to use in a circuit, thanks to its I2C interface. Below are the steps and considerations for integrating it into your project:

1. Power Supply: Connect the V_DD pin to a 2.7V to 5.5V power source and the GND pin to ground.
2. I2C Interface: Connect the SCL and SDA pins to the corresponding I2C lines of your microcontroller. Use pull-up resistors (typically 4.7kΩ) on both lines if not already present.
3. Output Voltage: The V_OUT pin provides the analog voltage output. Connect this pin to the desired load or circuit.
4. Address Selection: Use the A0 pin to set the I2C address. Tie it to GND or V_DD to select between two possible addresses.

Below is an example of how to use the MCP4735 with an Arduino UNO to generate an analog voltage:

• Connect MCP4735's V_DD to 5V and GND to GND on the Arduino.
• Connect SCL to A5 and SDA to A4 on the Arduino UNO.
• Use a pull-up resistor (4.7kΩ) on both SCL and SDA lines.

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

#define MCP4735_ADDR 0x60 // Default I2C address of MCP4735 (A0 = GND)

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

void loop() {
  uint16_t value = 512; // 10-bit DAC value (0 to 1023)
  
  // Send the value to the MCP4735
  Wire.beginTransmission(MCP4735_ADDR);
  Wire.write((value >> 8) & 0x0F); // Send the upper 4 bits of the 10-bit value
  Wire.write(value & 0xFF);        // Send the lower 8 bits of the 10-bit value
  Wire.endTransmission();
  
  Serial.println("DAC value sent: " + String(value)); // Debugging output
  delay(1000); // Wait for 1 second before sending the next value
}

• I2C Address: Ensure the correct I2C address is used in your code. The default address is 0x60 when A0 is tied to GND.
• Voltage Range: The output voltage range is from 0V to V_DD. Ensure your load is compatible with this range.
• Pull-up Resistors: Use appropriate pull-up resistors on the I2C lines if not already present in your circuit.

1. No Output Voltage:

   • Ensure the MCP4735 is powered correctly (V_DD and GND are connected).
   • Verify the I2C connections (SCL and SDA) and check for proper pull-up resistors.
   • Confirm the I2C address in your code matches the hardware configuration.

2. Incorrect Output Voltage:

   • Check the 10-bit value being sent to the DAC. Ensure it is within the range of 0 to 1023.
   • Verify the power supply voltage (V_DD) is stable and within the specified range.

3. I2C Communication Failure:

   • Ensure the SCL and SDA lines are not shorted or disconnected.
   • Check the pull-up resistors on the I2C lines.
   • Verify the I2C clock speed does not exceed 400 kHz.

Q: Can the MCP4735 output negative voltages?
A: No, the MCP4735 can only output voltages in the range of 0V to V_DD.

Q: What is the resolution of the MCP4735?
A: The MCP4735 has a 10-bit resolution, meaning it can output 1024 discrete voltage levels.

Q: Can I use the MCP4735 with a 3.3V microcontroller?
A: Yes, the MCP4735 operates with a supply voltage range of 2.7V to 5.5V, making it compatible with 3.3V systems.

Q: How do I change the I2C address of the MCP4735?
A: The I2C address is determined by the state of the A0 pin. Tie A0 to GND or V_DD to select between two possible addresses (0x60 or 0x61).