Infineon BSS131H6327XTSA1: N-Channel Logic Level MOSFET Datasheet and Application Review

The Infineon BSS131H6327XTSA1 is a surface-mount N-Channel Enhancement Mode MOSFET that has become a fundamental component in the designer's toolkit for low-voltage, low-power switching applications. As a logic-level MOSFET, it is specifically engineered to be driven directly from microcontrollers, logic ICs, and other low-voltage sources, making it an ideal choice for a vast array of modern electronics. This article provides a detailed review of its key specifications from the datasheet and explores its primary applications.

A core strength of the BSS131H6327XTSA1 lies in its exceptionally low threshold voltage (V_GS(th)). With a maximum value of just 1.5V, it can be fully turned on (saturated) with gate-source voltages commonly supplied by 3.3V or even 1.8V microcontroller GPIO pins. This eliminates the need for additional gate driver circuits, simplifying design and reducing both component count and board space.

The device is characterized by its low on-state resistance (R_DS(on)). With a typical R_DS(on) of 3.5 Ω at V_GS = 4.5 V and I_D = 0.17 A, it ensures minimal voltage drop and power loss when switched on. This high efficiency is crucial for battery-powered devices where every milliwatt of saved power translates directly into extended operational life.

Housed in a compact SOT-23 (TO-236AB) package, the BSS131 is designed for high-density PCB layouts. Its key electrical characteristics include a continuous drain current (I_D) of 170 mA and a drain-source voltage (V_DS) rating of 200 V. The high V_DS rating is particularly noteworthy for a small-signal MOSFET, offering a significant safety margin in low-power offline switch-mode power supplies (SMPS) and other circuits where voltage spikes may occur.

Application Circuits and Uses

The primary application for the BSS131H6327XTSA1 is as a high-efficiency switch for load control. Its most common uses include:

Low-Side Switching: Driving small relays, LEDs, solenoids, or DC motors from a microcontroller.

Signal Gating and Analog Switching: Muting audio signals or switching analog paths in consumer electronics.

SMPS Auxiliary Circuits: Used in startup or housekeeping circuits within power supplies due to its high voltage rating.

Level Shifting: Interfacing between circuits operating at different voltage levels.

A typical application circuit involves the MOSFET's drain connected to the load, the source to ground, and the gate to the microcontroller pin. A pull-down resistor between the gate and source is critical to ensure the MOSFET turns off reliably when the MCU pin is in a high-impedance state.

ICGOODFIND Summary

The Infineon BSS131H6327XTSA1 is a highly reliable and efficient logic-level MOSFET that excels in low-power switching tasks. Its standout features are its low threshold voltage, which ensures seamless compatibility with modern microcontrollers, and its surprisingly high drain-source voltage rating for its class. For designers seeking a robust, compact, and easy-to-use solution for controlling loads from low-voltage logic, the BSS131 remains a top-tier choice, perfectly balancing performance, size, and cost.

Keywords: Logic Level MOSFET, Low Threshold Voltage, SOT-23, Load Switch, Low-Side Switching.