How to Use IRLML6402: Examples, Pinouts, and Specs

The IRLML6402 is a low-voltage N-channel MOSFET manufactured by Infineon Technologies (Part ID: IRLML6402TRPBF). This component is designed for applications requiring high efficiency, low on-resistance, and fast switching speeds. Its compact SOT-23 package makes it ideal for space-constrained designs.

• Power management in portable devices
• DC-DC converters
• Load switching in battery-powered systems
• Motor control circuits
• General-purpose switching applications

The following table outlines the key technical specifications of the IRLML6402:

The IRLML6402 is housed in a 3-pin SOT-23 package. The pinout is as follows:

1. Power Supply: Ensure the drain-source voltage (V_DS) does not exceed 20V and the gate-source voltage (V_GS) stays within ±12V.
2. Gate Drive: Use a gate drive voltage of 4.5V or higher to fully turn on the MOSFET and achieve low on-resistance.
3. Load Connection: Connect the load between the drain pin and the positive supply voltage. The source pin should be connected to ground.
4. Gate Resistor: Add a resistor (typically 10Ω–100Ω) in series with the gate to limit inrush current and prevent oscillations.
5. Protection: Use a flyback diode across inductive loads to protect the MOSFET from voltage spikes during switching.

The IRLML6402 can be used to control a small DC motor with an Arduino UNO. Below is an example circuit and code:

• Connect the drain of the IRLML6402 to one terminal of the motor.
• Connect the other terminal of the motor to the positive supply (e.g., 12V).
• Connect the source of the IRLML6402 to ground.
• Connect the gate to an Arduino digital pin (e.g., D9) through a 100Ω resistor.
• Add a flyback diode (e.g., 1N4007) across the motor terminals to protect the MOSFET.

// IRLML6402 MOSFET Motor Control Example
// This code demonstrates how to control a DC motor using PWM.

const int motorPin = 9; // Pin connected to the MOSFET gate

void setup() {
  pinMode(motorPin, OUTPUT); // Set motorPin as an output
}

void loop() {
  // Gradually increase motor speed
  for (int speed = 0; speed <= 255; speed++) {
    analogWrite(motorPin, speed); // Write PWM signal to the gate
    delay(10); // Small delay for smooth ramp-up
  }

  delay(1000); // Run motor at full speed for 1 second

  // Gradually decrease motor speed
  for (int speed = 255; speed >= 0; speed--) {
    analogWrite(motorPin, speed); // Write PWM signal to the gate
    delay(10); // Small delay for smooth ramp-down
  }

  delay(1000); // Pause before repeating
}

• Avoid exceeding the maximum voltage and current ratings to prevent damage.
• Use proper heat dissipation techniques (e.g., PCB copper planes) to manage power dissipation.
• Ensure the gate drive voltage is sufficient to fully turn on the MOSFET for efficient operation.

1. MOSFET Overheating

   • Cause: Exceeding the maximum current or insufficient heat dissipation.
   • Solution: Check the load current and ensure proper cooling (e.g., heatsinks or PCB design).

2. MOSFET Not Switching

   • Cause: Insufficient gate drive voltage.
   • Solution: Verify that the gate voltage is at least 4.5V for full enhancement.

3. High Power Loss

   • Cause: Operating the MOSFET in the linear region instead of saturation.
   • Solution: Ensure the gate voltage is high enough to fully turn on the MOSFET.

4. Voltage Spikes

   • Cause: Inductive loads causing back EMF.
   • Solution: Add a flyback diode across the load to suppress voltage spikes.

Q1: Can the IRLML6402 handle 5V logic levels?
Yes, the IRLML6402 is designed to operate with logic-level gate drive voltages as low as 4.5V.

Q2: Is the IRLML6402 suitable for high-frequency switching?
Yes, the IRLML6402 has fast switching characteristics, making it suitable for high-frequency applications.

Q3: Can I use the IRLML6402 for 24V systems?
No, the maximum drain-source voltage (V_DS) is 20V. Exceeding this limit may damage the MOSFET.

Q4: What is the maximum current the IRLML6402 can handle?
The IRLML6402 can handle up to 3.7A continuously at 25°C, provided proper heat dissipation is ensured.