Microchip TC4468COE Quad CMOS Power MOSFET Driver IC Datasheet and Application Circuit Analysis

The Microchip TC4468COE is a quad, independent, inverting power MOSFET driver fabricated in CMOS technology, designed to deliver high peak output current from a low voltage input. It is particularly suited for applications requiring multiple, efficient gate drivers, such as in motor control systems, switching power supplies, and high-frequency interface circuits. This analysis delves into the device's key specifications from its datasheet and explores a typical application circuit.

Key Datasheet Specifications and Performance Characteristics

The TC4468COE operates over a wide supply voltage range from 4.5V to 18V, making it compatible with both 5V and 15V logic systems. Each of its four channels can source/sink a substantial peak current of 1.5A, enabling rapid switching of large capacitive loads like power MOSFETs and IGBTs. This high current capability is crucial for minimizing switching transitions, which directly reduces power loss and improves overall system efficiency.

A defining feature of this driver is its CMOS input structure. This provides high noise immunity and low input current, allowing it to be directly interfaced with a wide variety of logic families (CMOS, LSTTL, PIC® MCUs) without the need for additional pull-up or pull-down resistors. The inputs are also equipped with hysteresis (typically 0.8V), further enhancing its robustness against signal noise in electrically noisy environments.

The inverting logic of the TC4468COE means a logic HIGH at the input results in a LOW at the output, and vice versa. The outputs are staged in a totem-pole configuration, which is standard for providing both active pull-up and pull-down, ensuring sharp output transitions.

Internally, the device incorporates critical protection mechanisms. A latch-up protected design ensures the IC can survive voltage spikes beyond the supply rails. Furthermore, it is designed to withstand electrostatic discharges (ESD) of up to 4kV, safeguarding it during handling and operation.

Typical Application Circuit Analysis

A common application for one channel of the TC4468COE is driving a high-side N-channel MOSFET in a half-bridge or full-bridge configuration, as shown in the simplified circuit below.

```

[Microcontroller GPIO] ----> [TC4468COE Input] ----> [TC4468COE Output] ----> [Gate of Power MOSFET]

(e.g., Channel 1) (1.5A peak)

```

The microcontroller's GPIO pin (3.3V or 5V logic level) is connected directly to one of the driver's input pins. The driver's VDD pin is connected to a suitable supply voltage (e.g., 12V) to provide sufficient gate drive voltage for the MOSFET. The output pin is connected directly to the gate of the power MOSFET. A critical external component is the small series gate resistor (R_G, typically between 5-100Ω) placed between the driver's output and the MOSFET's gate.

The role of R_G is multifaceted: it controls the peak inrush current during switching, dampens high-frequency ringing caused by parasitic inductance and the MOSFET's gate capacitance, and can help reduce electromagnetic interference (EMI). The value of R_G is a trade-off: a lower value allows for faster switching and lower switching losses, but increases ringing and EMI; a higher value reduces noise and overshoot at the expense of slower switching and higher losses.

The driver's ability to source and sink high current ensures the MOSFET's gate capacitance (C_ISS) is charged and discharged very quickly, slamming the MOSFET through its linear region and minimizing the time spent in a high-resistance, high-power-dissipation state.

ICGOODFIND Summary

The Microchip TC4468COE stands out as a robust and versatile solution for driving multiple power MOSFETs. Its quad independent channel architecture, high 1.5A peak output current, and wide operating voltage range offer designers significant flexibility. The CMOS inputs with hysteresis provide excellent noise immunity for reliable operation in harsh environments. When implemented with careful selection of external gate resistors, this driver IC forms the foundation of efficient, fast-switching, and reliable power electronic circuits.

Keywords:

MOSFET Driver

CMOS Technology

High Peak Current

Gate Drive Circuit

Noise Immunity