Microchip TC426CPA Dual MOSFET Driver: Datasheet, Application Circuit, and Pinout Configuration
The Microchip TC426CPA is a versatile and robust dual MOSFET driver IC designed to efficiently drive the gates of power MOSFETs and IGBTs in a wide array of switching applications. This device is particularly valued for its ability to provide the high peak current necessary to rapidly switch capacitive loads, thereby minimizing switching losses and improving overall system efficiency. Housed in an 8-pin PDIP package, the TC426CPA is a through-hole component ideal for prototyping and industrial applications.
Pinout Configuration
Understanding the pinout is crucial for proper circuit design. The TC426CPA features two independent driver channels.
Pin 1 (OUT A): Output of Driver A.
Pin 2 (GND): Ground reference for the IC.
Pin 3 (IN A): Input for Driver A.
Pin 4 (Vdd): Positive supply voltage (typically +4.5V to +18V).
Pin 5 (IN B): Input for Driver B.
Pin 6 (NC): No Connection.
Pin 7 (GND): Ground reference for the IC.
Pin 8 (OUT B): Output of Driver B.
The presence of two ground pins (2 and 7) enhances stability by providing a lower impedance path for return currents. The inputs (IN A, IN B) are TTL/CMOS compatible, allowing for direct interfacing with logic circuits from microcontrollers or DSPs.
Key Datasheet Specifications
The datasheet provides the essential electrical characteristics and absolute maximum ratings that define the operational boundaries of the IC.
High Peak Output Current: Up to 1.5A, enabling very fast switching of large MOSFETs.
Wide Operating Voltage Range (Vdd): From 4.5V to 18V, offering flexibility in various system voltages.
Fast Propagation Delay: Typically 55ns, ensuring precise timing control in high-frequency circuits.
Matched Rise/Fall Times: Typically 25ns with a 1,000pF load, which helps in reducing transition times.
Low Supply Current: Typically 2.5mA per driver, making it efficient for power-sensitive designs.
Latch-Up Protected: Can withstand over 500mA on the output without damage.
Application Circuit
A typical application circuit for one channel of the TC426CPA involves using it as an interface between a low-power logic signal (e.g., from a PWM controller) and the gate of a high-power MOSFET in a switch-mode power supply or motor drive circuit.
The input pin (IN A) is connected to the source signal, often through a small resistor to dampen any ringing. The Vdd pin is decoupled to ground with a low-ESR electrolytic capacitor (e.g., 10µF) and a high-frequency ceramic capacitor (e.g., 100nF) placed as close as possible to the IC to handle the high peak currents during switching. The output pin (OUT A) is connected directly to the gate of the MOSFET. A critical component in this circuit is a small series resistor (e.g., 10Ω) placed between the driver output and the MOSFET gate. This resistor is essential for damping parasitic oscillations and controlling the peak current inrush, which can otherwise lead to ringing and electromagnetic interference (EMI).
For switching inductive loads or in bridge configurations, a pull-down resistor or an active pull-down circuit may be added to ensure the MOSFET turns off completely.
The Microchip TC426CPA stands out as a reliable and efficient solution for driving power MOSFETs and IGBTs. Its high peak current capability, fast switching speeds, and robust protection features make it an excellent choice for applications demanding precision and efficiency, such as switch-mode power supplies (SMPS), motor controllers, and Class D amplifiers. Its through-hole package makes it particularly accessible for development and testing.
Keywords:
1. MOSFET Driver
2. Gate Driving
3. Switching Speed
4. Peak Output Current
5. Application Circuit
