How to Use Pololu MD03A Dual VNH2SP30 Motor Driver: Examples, Pinouts, and Specs

The Pololu MD03A Dual VNH2SP30 Motor Driver (Manufacturer Part ID: 708) is a robust and efficient motor driver designed to control two DC motors independently. It is based on the VNH2SP30 full-bridge motor driver ICs, offering high current handling capabilities of up to 30A per channel with built-in thermal protection and current sensing. This makes it an excellent choice for robotics, automation, and other high-power motor control applications.

• Robotics (e.g., driving wheels or tracks)
• Automated guided vehicles (AGVs)
• Conveyor belt systems
• Remote-controlled vehicles
• Industrial automation systems

The following table outlines the key technical details of the Pololu MD03A motor driver:

The Pololu MD03A motor driver has a total of 16 pins. The table below describes each pin:

1. Power Connections:

   • Connect the motor power supply to the VIN pin and ground to the GND pin.
   • Ensure the supply voltage is within the range of 5.5V to 16V.
   • Connect the logic voltage (3.3V or 5V) to the VDD pin.

2. Motor Connections:

   • Connect the two terminals of Motor A to OUTA1 and OUTA2.
   • Connect the two terminals of Motor B to OUTB1 and OUTB2.

3. Control Signals:

   • Use the INA1/INA2 and INB1/INB2 pins to control the direction of Motor A and Motor B, respectively.
   • Provide a PWM signal to the PWM A and PWM B pins to control the speed of Motor A and Motor B.
   • Enable the motors by setting the ENA and ENB pins high.

4. Current Sensing:

   • Monitor the current draw of Motor A and Motor B using the CS A and CS B pins. The output voltage is proportional to the motor current (approximately 0.13V/A).

5. Diagnostics:

   • Use the DIAGA and DIAGB pins to detect faults such as over-temperature or over-current conditions. These pins go low when a fault is detected.

• Use a power supply capable of providing sufficient current for your motors.
• Add a capacitor (e.g., 100 µF) across the VIN and GND pins to reduce voltage spikes.
• Ensure proper heat dissipation, especially when operating at high currents.
• Avoid exceeding the maximum voltage and current ratings to prevent damage.
• Use pull-down resistors on unused input pins to avoid floating states.

Below is an example Arduino sketch to control two DC motors using the Pololu MD03A motor driver:

// Define motor control pins
#define INA1 2  // Motor A direction control pin 1
#define INA2 3  // Motor A direction control pin 2
#define ENA 9   // Motor A enable (PWM) pin
#define INB1 4  // Motor B direction control pin 1
#define INB2 5  // Motor B direction control pin 2
#define ENB 10  // Motor B enable (PWM) pin

void setup() {
  // Set motor control pins as outputs
  pinMode(INA1, OUTPUT);
  pinMode(INA2, OUTPUT);
  pinMode(ENA, OUTPUT);
  pinMode(INB1, OUTPUT);
  pinMode(INB2, OUTPUT);
  pinMode(ENB, OUTPUT);
}

void loop() {
  // Motor A: Forward at 50% speed
  digitalWrite(INA1, HIGH);
  digitalWrite(INA2, LOW);
  analogWrite(ENA, 128); // PWM value (0-255)

  // Motor B: Reverse at 75% speed
  digitalWrite(INB1, LOW);
  digitalWrite(INB2, HIGH);
  analogWrite(ENB, 192); // PWM value (0-255)

  delay(2000); // Run motors for 2 seconds

  // Stop both motors
  analogWrite(ENA, 0);
  analogWrite(ENB, 0);

  delay(2000); // Wait for 2 seconds
}

1. Motors not running:

   • Ensure the ENA and ENB pins are set high or receiving a valid PWM signal.
   • Verify that the power supply voltage is within the specified range.

2. Overheating:

   • Check for excessive current draw from the motors.
   • Ensure proper ventilation or add a heatsink to the motor driver.

3. Fault indication (DIAGA/DIAGB pins low):

   • Check for over-current or over-temperature conditions.
   • Reduce the motor load or improve cooling.

4. Erratic motor behavior:

   • Verify that all control signals are properly connected and not floating.
   • Add decoupling capacitors to reduce noise.

Q: Can I use this motor driver with a 24V motor?
A: No, the maximum operating voltage is 16V. Using a higher voltage may damage the driver.

Q: How do I measure motor current?
A: Connect the CS A or CS B pin to an analog input on your microcontroller. The voltage output is proportional to the motor current (approximately 0.13V/A).

Q: What happens if the motor stalls?
A: The driver has built-in thermal and over-current protection. If a stall causes excessive current, the driver will shut down to prevent damage.

Q: Can I control the motor driver with a Raspberry Pi?
A: Yes, the logic inputs are compatible with 3.3V signals, making it suitable for use with a Raspberry Pi.