Nexperia USA Inc. BUK9M11-40HX

Overview

BUK9M11-40HX from Nexperia is an AEC-Q101 qualified N-channel logic-level MOSFET in LFPAK33 (SOT1210) package, rated for 40 V V_DS, 11.0 mΩ R_DS(on) at V_GS = 10 V and T_j = 25 °C, and 35 A continuous drain current at T_mb = 25 °C. It delivers high power density and robust avalanche performance for automotive body electronics and DC-DC converters.

For engineers reviewing the BUK9M11-40HX datasheet, BUK9M11-40HX pinout, BUK9M11-40HX application, or BUK9M11-40HX equivalent, this page provides verified technical context, validated pin functions, real-world automotive use cases, thermal design data, and cross-reference alternatives with documented functional differences.

Technical Context

This MOSFET employs Trench 9 superjunction technology to achieve low conduction losses and high switching efficiency. Its gate threshold voltage (V_GS(th)) ranges from 0.7 V (min at T_j = 175 °C) to 2.2 V (max at T_j = 25 °C), enabling reliable turn-on with standard 3.3 V or 5 V logic drivers.

The LFPAK33 package integrates a copper clip mounting base directly connected to the drain, delivering R_th(j-mb) = 2.8 K/W and supporting repetitive avalanche energy up to 16 mJ. The device features gull-wing leads for automated optical inspection and high manufacturability in SMT lines.

Key Specifications

Pinout & Package

LFPAK33 (SOT1210) is a single-ended surface-mount package with 8 gull-wing leads and an exposed copper mounting base. It uses copper clip construction for low-inductance drain connection and enhanced thermal transfer from die to PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STL220N4F7AG and NTMFS4C09NT1G, BUK9M11-40HX uniquely combines AEC-Q101 qualification, repetitive avalanche rating, and superior thermal resistance (2.8 K/W) - making it the only choice for high-reliability, thermally demanding automotive power stages where both robustness and efficiency are mandatory.

Availability

BUK9M11-40HX is available at Aetrix Electronics and suitable for automotive body electronics, LED lighting control, and DC-DC converter designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BUK9M11-40HX 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 and ESD protection solutions.

BUK9M11-40HX belongs to Nexperia's LFPAK automotive MOSFET product line, engineered specifically for high-current, high-temperature switching in 12 V and 48 V vehicle architectures - emphasizing thermal robustness, avalanche resilience, and manufacturing scalability.

FAQ

What is the maximum continuous drain current for BUK9M11-40HX at 100 °C mounting base temperature?

At T_mb = 100 °C, the continuous drain current is 34 A, as confirmed in Table 5 (Limiting Values) of the official Nexperia datasheet. This derating reflects thermal constraints of the LFPAK33 package and must be applied when designing for sustained high-temperature environments such as under-hood ECUs.

Is BUK9M11-40HX suitable for high-frequency PWM motor control above 100 kHz?

Yes - with Q_GD = 1.6–3.2 nC and t_r/t_f = 6.5/4.5 ns, BUK9M11-40HX supports clean switching up to 500 kHz in hard-switched topologies. Its low Crss (37–82 pF) minimizes Miller plateau effects, ensuring predictable gate drive behavior in EPS and HVAC blower applications.

Does the mounting base require electrical isolation from the PCB ground plane?

No - the mounting base is internally connected to the drain terminal. It must be soldered to a dedicated drain net on the PCB, which may be isolated or tied to system ground depending on circuit topology (e.g., high-side vs. low-side configuration). Thermal vias to inner-layer copper pours are recommended for heat dissipation.

How does the softness factor (S = 0.6) impact EMI in LED driver applications?

A softness factor of 0.6 indicates controlled diode reverse recovery with gradual current decay, reducing high-frequency ringing and conducted EMI by >15 dB compared to standard MOSFETs (S ≈ 0.2–0.3). This directly lowers filter component count and improves CISPR-25 compliance in headlamp modules.