Microchip TC1426COA Dual 2A MOSFET Driver: Datasheet, Pinout, and Application Circuit Guide
The efficient control of power MOSFETs and IGBTs is a critical requirement in modern switching power supplies, motor controllers, and Class-D amplifiers. The Microchip TC1426COA stands out as a robust and reliable solution designed specifically for this demanding task. This dual, non-inverting driver is capable of delivering peak output currents of 2A, enabling it to swiftly charge and discharge the large capacitive gates of power MOSFETs, thereby minimizing switching losses and improving overall system efficiency.
This guide provides a detailed overview of the TC1426COA, covering its key specifications from the datasheet, pinout configuration, and a practical application circuit to help you integrate it successfully into your designs.
Datasheet Overview and Key Specifications
The TC1426COA is a member of Microchip's TC1426/27/28 family of dual MOSFET drivers. It is built with CMOS technology, which offers low power consumption and high noise immunity. Here are the critical specifications extracted from its datasheet:
High Peak Output Current: ±2A (sink and source) allows for very fast switching of large MOSFETs.
Dual Channels: Contains two independent, identical drivers in one package, which is ideal for driving both high-side and low-side switches in a half-bridge or full-bridge configuration.
Wide Operating Voltage Range: 4.5V to 18V, providing flexibility for various logic levels and bus voltages.
Fast Switching Speeds: Features low propagation delays (typically 55ns) and matched rise/fall times, which are crucial for high-frequency applications to prevent shoot-through.
Low Supply Current: Requires only 0.6mA (typical) of quiescent current per driver, reducing overall system power draw.
Latch-Up Protection: Can withstand > 500 mA latch-up current, enhancing robustness in harsh electrical environments.
Package: Available in an 8-pin SOIC (Small Outline Integrated Circuit) package, which is common and easy to prototype with.
Pinout Configuration
Understanding the pinout is essential for proper PCB layout and circuit design. The TC1426COA comes in an 8-pin SOIC package.
1. VddA (Pin 1): Supply voltage input for Driver A.
2. Input A (Pin 2): TTL/CMOS compatible input signal for Driver A.
3. Output A (Pin 3): Output of Driver A. Connects directly to the gate of the MOSFET.
4. GND (Pin 4): Ground reference for the IC.
5. Output B (Pin 5): Output of Driver B. Connects directly to the gate of the MOSFET.
6. Input B (Pin 6): TTL/CMOS compatible input signal for Driver B.
7. VddB (Pin 7): Supply voltage input for Driver B.
8. N/C (Pin 8): No Connection. This pin is not internally connected.
A key feature to note is the separate Vdd and GND pins for each driver (Pins 1, 7 and 4). This allows designers to use isolated power supplies for each channel, which is a common requirement in bridge circuits to accommodate different voltage domains.
Application Circuit Guide: Half-Bridge Configuration
A primary application for a dual driver like the TC1426COA is in a half-bridge circuit, common in motor drives and switch-mode power supplies (SMPS).
Circuit Setup:
1. Power Supplies: Two floating power supplies are often needed. The low-side driver (Driver A) can be powered by the main system Vdd (e.g., 12V) referenced to ground (Pin 4). The high-side driver (Driver B) must be powered by a bootstrap circuit or an isolated supply, with its VddB (Pin 7) referenced to the switch node (the connection point between the two MOSFETs).
2. Input Signals: The input signals (to Pins 2 and 6) must be provided by a microcontroller or PWM controller. It is absolutely critical that these signals have a dead time (a short period where both signals are low) to prevent the high-side and low-side MOSFETs from conducting simultaneously, a condition known as "shoot-through" which can cause catastrophic failure.
3. Outputs and Gate Resistors: The outputs (Pins 3 and 5) connect to the respective MOSFET gates. A small series gate resistor (e.g., 5-10Ω) is highly recommended for each output. This resistor helps dampen ringing caused by parasitic inductance and the MOSFET's gate capacitance, preventing oscillation and potentially damaging overshoot.
4. Decoupling Capacitors: Place a high-frequency decoupling capacitor (e.g., 0.1µF ceramic) as close as possible to each Vdd pin (1 & 7) and the GND pin (4). A larger bulk capacitor (e.g., 10µF electrolytic) may also be used on the main supply rail. This is vital to provide the instantaneous current needed during switching transitions and to maintain stable voltage.
ICGOODFIND: The Microchip TC1426COA is an exceptionally capable and robust dual MOSFET driver. Its high 2A peak current, fast switching speeds, and independent dual-channel design make it an excellent choice for high-performance applications like half-bridge and full-bridge motor controllers, efficient SMPS, and high-power audio amplifiers. Proper implementation, including careful attention to power supply decoupling, gate resistors, and input signal timing, is key to unlocking its full potential and ensuring a reliable design.
Keywords: MOSFET Driver, Half-Bridge, TC1426COA, Gate Driving, Switching Speed
