Infineon SN7002N N-Channel Enhancement Mode Field Effect Transistor (FET) Datasheet and Application Overview

The Infineon SN7002N is a widely utilized N-Channel Enhancement Mode Field Effect Transistor (FET) designed for low-power switching applications. Renowned for its reliability and cost-effectiveness, this small-signal MOSFET is a fundamental component in a vast array of electronic circuits, from consumer electronics to industrial control systems. This article provides an overview of its key characteristics, as detailed in its datasheet, and explores its primary applications.

Key Electrical Characteristics and Features

Housed in a compact SOT-23 package, the SN7002N is engineered for low-voltage, low-current operations. Its enhancement mode nature means that the device remains off when the gate-source voltage (V_GS) is zero, requiring a positive voltage to form a conductive channel and turn the transistor on.

The absolute maximum ratings define the operational boundaries of the device. Critical among these are a drain-source voltage (V_DS) of 60V and a gate-source voltage (V_GS) of ±12V. These ratings ensure the FET can handle a significant voltage range in various circuit conditions. The device can support a continuous drain current (I_D) of up to 200mA, making it suitable for driving small relays, LEDs, and other peripheral components.

The threshold voltage (V_GS(th)), typically around 1V, is notably low. This characteristic is crucial as it allows the SN7002N to be easily driven directly from 5V logic levels, such as those from microcontrollers (e.g., Arduino, ESP32) or standard logic ICs, without requiring a level-shifter or complex driver circuit. Furthermore, it boasts a very low on-state resistance (R_DS(on)), typically just 5 ohms, which minimizes power loss and voltage drop across the device when it is fully saturated.

Primary Applications and Circuit Implementation

The SN7002N excels in a multitude of low-side switching roles. Its most common function is as an interface between microcontrollers and higher-power devices. A typical application circuit involves connecting the drain pin to the load (e.g., an LED strip, a small DC motor) and the source pin to ground. The microcontroller's GPIO pin is connected to the gate through a current-limiting resistor (often 100Ω to 1kΩ). When the GPIO output is set to a logic HIGH (5V), which is well above the threshold voltage, the FET switches on, allowing current to flow through the load to ground. A pull-down resistor on the gate pin is often recommended to ensure the FET turns off reliably when the microcontroller pin is in a high-impedance state.

Beyond simple switching, the SN7002N is also employed in load drivers, analog switches, and in fast switching circuits for signal routing. Its fast switching speeds make it adequate for applications requiring rapid on/off cycling.

Conclusion and Design Considerations

When designing with the SN7002N, it is vital to operate within its Absolute Maximum Ratings to ensure long-term reliability. Designers should pay close attention to:

Gate-Source Voltage Protection: Ensuring V_GS never exceeds ±12V to prevent damage to the sensitive gate oxide layer.

Adequate Gate Driving: Providing a sufficient gate voltage (e.g., 5V or 10V) to drive the FET into full saturation, minimizing R_DS(on) and thus power dissipation.

Transient Suppression: In circuits with inductive loads (like motors or relays), a protection diode should be used to clamp voltage spikes and protect the FET.

ICGOODFIND: The Infineon SN7002N stands as an exceptionally versatile and robust solution for low-power switching tasks. Its ability to be directly controlled by logic-level signals, combined with its high voltage tolerance and low on-resistance, makes it an indispensable component for engineers and hobbyists alike, bridging the gap between digital control and analog power.

Keywords:

1. N-Channel MOSFET

2. Enhancement Mode

3. Logic-Level Gate Drive

4. Low On-Resistance (R_DS(on))

5. SOT-23 Package