Infineon BSS127: Key Specifications and Application Circuit Design Guide

The Infineon BSS127 is a popular N-channel enhancement mode logic level MOSFET, widely recognized for its efficiency in low-voltage applications. Designed with Infineon’s advanced trench technology, this small-signal MOSFET offers low threshold voltage, high switching performance, and minimal on-state resistance, making it ideal for portable electronics, power management circuits, and load switching systems.

Key Specifications:

- Drain-Source Voltage (V_DS): 200V

- Continuous Drain Current (I_D): 130 mA

- On-Resistance (R_DS(on)): 35 Ω at 10V, 50 mA

- Gate Threshold Voltage (V_GS(th)): 1.5V–3V

- Package: SOT-23

These specifications highlight the device’s suitability for low-power applications where space and energy efficiency are critical.

Application Circuit Design Guide:

A common use case for the BSS127 is in low-side switch configurations. Below is a typical circuit for driving a DC load such as a small motor or LED strip:

1. Component Selection:

- Supply Voltage (V_DD): 3.3V–12V

- Load (e.g., resistor, LED, motor) connected between drain and V_DD

- Gate driven directly by a microcontroller GPIO (3.3V or 5V)

- Optional pull-down resistor (10kΩ) from gate to ground for stable off-state

2. Gate Driving Consideration:

Since the BSS127 is a logic-level MOSFET, it can be fully turned on with a 3.3V or 5V signal, simplifying interface with digital controllers.

3. Protection Measures:

- Use a series gate resistor (e.g., 100Ω) to limit inrush current and damp oscillations.

- For inductive loads, include a flyback diode across the load to protect against voltage spikes.

4. Performance Tips:

- Ensure the gate voltage exceeds V_GS(th) sufficiently to minimize R_DS(on).

- Avoid exceeding absolute maximum ratings, especially in V_GS (±20V) and I_D.

Example Circuit: Arduino-Based Switch

Connect the source pin to ground, the drain to the negative terminal of a 12V LED strip, and the gate to an Arduino digital pin via a 100Ω resistor. The positive LED supply connects to 12V. A sketch setting the pin HIGH turns the MOSFET ON, completing the circuit.

ICGOOODFIND:

The Infineon BSS127 stands out for its high voltage capability, compact form factor, and ease of integration in low-power control circuits, offering designers a reliable and cost-effective solution for switching and amplification tasks.

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Keywords:

Logic Level MOSFET, Low Threshold Voltage, Application Circuit, SOT-23 Package, Low-Side Switch