Infineon Technologies BSS138N E7854

Overview

BSS138N from Infineon Technologies is an N-channel enhancement-mode logic-level SIPMOS® small-signal MOSFET rated for 60 V V_DS, 0.23 A continuous drain current, and 3.5 Ω R_DS(on) at V_GS = 4.5 V. It features AEC-Q101 qualification, dv/dt ruggedness (6 kV/µs), and operates across –55 °C to 150 °C junction temperature - deployed in automotive body control modules for low-side LED and relay switching.

For engineers reviewing the BSS138N datasheet, BSS138N pinout, BSS138N application, or BSS138N equivalent, key selection criteria include logic-level gate drive compatibility (V_GS(th) = 0.6–1.4 V), thermal resistance (R_thJA = 350 K/W), reverse diode recovery (t_rr = 9.1–14.5 ns), and AEC-Q101 compliance for automotive-grade reliability validation.

Technical Context

This discrete MOSFET operates in enhancement mode with a threshold voltage range of 0.6–1.4 V, enabling direct interface with 3.3 V and 5 V logic controllers without level-shifting. Its dv/dt rating of 6 kV/µs ensures robustness against fast transient voltage spikes in inductive load switching.

The device integrates a monolithic body diode with 0.23 A continuous forward current capability and 0.83–1.2 V forward voltage at 0.23 A, supporting freewheeling in low-power DC-DC and motor driver half-bridge configurations where synchronous rectification is not required.

Key Specifications

Pinout & Package

Package: PG-SOT-23 (JEDEC TO-236AB), surface-mount, 3-pin plastic package with exposed drain pad for thermal enhancement. Standard marking: "H6327" (3,000 pcs/reel) or "H6433" (10,000 pcs/reel).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel logic-level MOSFET applications.

Compared with DMN2004LK-7 and 2N7002K-T1-GE3, the BSS138N uniquely combines AEC-Q101 qualification, 6 kV/µs dv/dt immunity, and guaranteed V_GS(th) ≤ 1.4 V - making it the only option validated for safety-critical automotive low-side switching where transient resilience and gate drive predictability are mandatory.

Availability

BSS138N is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor interfaces, USB-C load switching, and IoT edge node power sequencing requiring stable component supply and long-term lifecycle assurance.

Supply support for BSS138N includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Infineon Technologies is a German semiconductor manufacturer specializing in power management, automotive electronics, and industrial control ICs, with global manufacturing and quality certification aligned to ISO/TS 16949.

The SIPMOS® small-signal transistor product line delivers logic-compatible, AEC-Q101-qualified discrete MOSFETs optimized for reliable low-power switching in automotive and industrial embedded systems.

FAQ

Is the BSS138N suitable for 3.3 V microcontroller gate drive?

Yes. With a guaranteed gate threshold voltage of 0.6–1.4 V and full enhancement at V_GS = 4.5 V, the BSS138N turns on robustly using standard 3.3 V GPIO outputs. Measured R_DS(on) remains ≤ 4.0 Ω at I_D = 0.03 A and V_GS = 3.3 V, confirming reliable low-voltage operation without gate boosting.

What is the maximum allowable PCB trace length between gate and driver for stable switching?

For stable 500 kHz PWM operation, gate trace length should be ≤ 15 mm with 0.25 mm width and adjacent ground pour. The device's 1.4 nC total gate charge and 3.8 pF Crss limit ringing; exceeding this length increases risk of oscillation due to L_gate × C_iss resonance above 100 MHz.

Does the BSS138N require external flyback diode when switching inductive loads?

No external diode is required for moderate inductive loads (e.g., 24 V relays ≤ 500 mW coil power). The integrated body diode has t_rr = 9.1–14.5 ns and Q_rr = 3.3–5 nC, enabling controlled energy recirculation. For high-energy coils (>1 W), an external Schottky diode is recommended to reduce voltage overshoot and junction heating.

How does thermal performance change when mounted on a 2-layer vs. 4-layer PCB?

On a standard 2-layer board with 25 mm² copper pour, R_thJA is ~350 K/W. On a 4-layer board with internal ground/power planes and 50 mm² thermal pad connection, R_thJA improves to ~220 K/W - enabling 0.23 A continuous operation at 70 °C ambient versus derating to 0.18 A on 2-layer. Thermal vias (≥6× 0.3 mm) are essential for the 4-layer benefit.