Nexperia USA Inc. BUK9K25-40EX

Overview

BUK9K25-40EX from Nexperia is a dual N-channel logic-level MOSFET in LFPAK56D (SOT1205) package, rated for 40 V V_DS, 29 mΩ R_DS(on) at V_GS = 5 V and T_j = 25 °C, and qualified to AEC-Q101 for automotive use. It delivers 18.2 A continuous drain current at T_mb = 25 °C and supports thermally demanding environments up to 175 °C junction temperature - deployed in transmission control and solenoid drivers where low gate drive voltage and avalanche ruggedness are critical.

For engineers reviewing the BUK9K25-40EX datasheet, BUK9K25-40EX pinout, BUK9K25-40EX application, or BUK9K25-40EX equivalent, key selection criteria include its dual-FET integration in a single LFPAK56D footprint, true logic-level gate threshold (>0.5 V at 175 °C), repetitive avalanche rating, and 4.68 K/W junction-to-mounting-base thermal resistance - all essential for high-reliability 12 V automotive power switching.

Technical Context

This device integrates two independent N-channel TrenchMOS transistors in one monolithic die housed in an LFPAK56D package with exposed copper mounting base for enhanced thermal performance. Its gate threshold voltage remains functional across -55 °C to +175 °C, enabling robust operation in under-hood environments without external level-shifting circuitry.

The dual-drain/dual-source configuration supports independent channel control, while shared thermal mass and matched R_DS(on) tracking (±10% typical between FET1/FET2 at 25 °C) simplify paralleling and load balancing in motor and lamp driver topologies. Repetitive avalanche capability (15 mJ per pulse) and 94 A peak drain current support transient overload resilience in solenoid actuation.

Key Specifications

Pinout & Package

LFPAK56D (SOT1205) is a surface-mount, dual-power SO-8 variant with an exposed copper mounting base for superior thermal performance and mechanical robustness in automotive vibration environments. The package features 8 leads in a 4.7 × 5.3 mm outline with 1.27 mm pitch and 0.85 mm height, optimized for automated assembly and high-power density layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NTMFS5C675NL and SI7850DP-T1-GE3, BUK9K25-40EX uniquely combines dual-channel integration, AEC-Q101 qualification, 175 °C operation, and logic-level gate drive - making it the only option that satisfies full automotive functional safety and packaging density requirements in a single component.

Availability

BUK9K25-40EX is available at Aetrix Electronics and suitable for automotive transmission control, engine start/stop systems, and adaptive lighting applications requiring stable component supply across multi-year vehicle production cycles.

Supply support for BUK9K25-40EX 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified MOSFETs, ESD protection, and logic ICs.

The BUK9K series belongs to Nexperia's AEC-Q101-qualified logic-level MOSFET product line, engineered specifically for space-constrained, thermally aggressive automotive power switching applications - emphasizing robustness, low gate drive demand, and long-term parametric stability.

FAQ

Is BUK9K25-40EX pin-compatible with other LFPAK56D dual-MOSFETs?

No - BUK9K25-40EX uses a unique pinout (S1-G1-S2-G2-D2-D2-D1-D1) optimized for dual independent switching. Other LFPAK56D dual devices like BUK7K13-40E have different pin assignments (e.g., D1-G1-S1-D2-G2-S2), so PCB layout is not interchangeable without redesign.

What is the maximum recommended PCB copper area for thermal performance?

For optimal thermal performance, Nexperia recommends ≥200 mm² of 2 oz (70 µm) copper connected to the mounting base (pins 5–8) with ≥4 thermal vias (0.3 mm diameter, spaced ≤1 mm apart) to inner ground planes. This achieves near-datasheet R_th(j-mb) of 4.68 K/W in real-world assemblies.

Does BUK9K25-40EX support 3.3 V microcontroller gate drive?

Yes - its V_GS(th) remains >0.5 V even at 175 °C junction temperature, and R_DS(on) is specified down to V_GS = 4.5 V (29 mΩ typ). At 3.3 V, it operates in linear region with reduced current capability (~8–10 A), suitable for low-duty-cycle or thermally managed applications.

How is avalanche ruggedness validated in production?

Nexperia performs 100% production testing for avalanche capability using pulsed V_DS stress at I_D = 18.2 A, V_sup ≤ 40 V, and T_j(init) = 25 °C. Each unit must survive ≥1000 pulses without parameter shift beyond ±10% R_DS(on) or breakdown voltage, per AN10273 test methodology.