onsemi FAN3225TMX 4A Gate Driver: Datasheet, Application Circuit, and Pinout Configuration

The onsemi FAN3225TMX is a high-performance, 4A single-channel gate driver designed to efficiently drive MOSFETs and IGBTs in a wide range of power conversion applications. Its ability to deliver high peak current pulses makes it an ideal choice for switching power supplies, motor control, and Class-D amplifiers where fast switching speeds and minimal crossover conduction are critical for efficiency and thermal performance.

This gate driver is part of onsemi's extensive portfolio, renowned for robustness and reliability. The device features TTL and CMOS compatible input thresholds, allowing for easy interfacing with both 3.3V and 5V logic controllers from microcontrollers or DSPs. A key attribute of the FAN3225TMX is its split output configuration, which provides independent sink and source connections. This allows for precise control over the turn-on and turn-off speeds of the power switch by enabling the use of separate gate resistors, optimizing switching performance and controlling EMI.

Pinout Configuration

The FAN3225TMX is available in a space-saving 8-pin SOIC package. The pinout is as follows:

1. VDD: Positive supply voltage pin for the output driver stage.

2. IN: Input pin. The state of this logic-level input controls the output.

3. GND: Ground reference pin.

4. NC: No internal connection.

5. LO: The output of the driver for the lower switch (in a half-bridge configuration). Internally connected to HO in this single-channel version.

6. HO: The output of the driver for the upper switch. Internally connected to LO.

7. VSS: Negative supply rail for the output driver. Typically connected to the source of the power MOSFET.

8. NC: No internal connection.

Note: For the FAN3225TMX, the HO and LO pins are internally connected, forming a single output channel.

Key Datasheet Specifications

Supply Voltage (VDD): 7V to 20V range

Peak Output Current: ±4A (sink and source)

Propagation Delay (tPD): 18 ns (typical)

Rise/Fall Time: 10 ns (typical with 1.8nF load)

Under-Voltage Lockout (UVLO): ~6.7V (on) / ~6.4V (off)

Operating Temperature: -40°C to +125°C

Typical Application Circuit

A common application for the FAN3225TMX is driving a high-side N-channel MOSFET. A typical circuit includes:

1. A decoupling capacitor (e.g., 1µF ceramic) placed very close to the VDD and GND pins to provide the high peak current required during switching.

2. A series gate resistor (Rg) on the output path to control the switching speed, dampen ringing, and prevent oscillations. The value is typically between 2.2Ω and 10Ω.

3. An optional pull-down resistor (e.g., 100kΩ) on the input (IN) pin to ensure a known state (off) if the driving microcontroller pin is in a high-impedance state during startup.

4. The source of the MOSFET is connected to the VSS pin of the driver to provide a stable reference for the gate drive signal.

ICGOODFIND: The onsemi FAN3225TMX stands out as a robust and versatile solution for modern power electronics. Its high 4A drive strength, extremely fast switching characteristics, and simple interface make it an excellent choice for designers looking to improve efficiency, reduce size, and enhance the reliability of their power switching stages. Its internal connection of HO and LO simplifies its use as a powerful single-channel driver for both low-side and high-side applications with a bootstrap circuit.

Keywords: Gate Driver, 4A Peak Current, MOSFET/IGBT Driver, High-Speed Switching, SOIC-8 Package.