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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

Nexperia USA Inc. BUK9M14-40EX

Name: BUK9M14-40EX
Brand: Nexperia USA Inc.
SKU: BUK9M14-40EX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUK9M14-40EX

Manufacturer:: Nexperia USA Inc.

Category:: FETs, MOSFETs

Package:: SOT-1210, 8-LFPAK33 (5-Lead)

Datasheet:: BUK9M14-40EX.pdf

Description:: MOSFET N-CH 40V 44A LFPAK33

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Product details

Overview

BUK9M14-40EX from Nexperia is an AEC-Q101 qualified N-channel logic-level MOSFET in LFPAK33 (SOT1210) package, rated for 40 V V_DS, 14 mΩ R_DS(on) at V_GS = 5 V and T_j = 25 °C, and 175 °C junction operation - designed for high-reliability 12 V automotive power switching in transmission control, lamp drivers, and solenoid interfaces.

For engineers reviewing the BUK9M14-40EX datasheet, BUK9M14-40EX pinout, BUK9M14-40EX application, or BUK9M14-40EX equivalent, this device delivers verified repetitive avalanche ruggedness, true logic-level gate drive down to 0.5 V threshold at 175 °C, and 2.46 K/W junction-to-mounting-base thermal resistance - critical for thermally constrained automotive PCB layouts.

Technical Context

This MOSFET uses TrenchMOS technology to achieve low on-resistance with fast switching dynamics: Q_GD = 4.8 nC and t_f = 12.2 ns enable efficient PWM control in motor and load switching circuits. Its LFPAK33 package integrates a drain-connected mounting base for direct thermal coupling to heatsinks or copper planes.

The device features a robust source-drain diode (V_SD = 0.85 V at I_S = 15 A, T_j = 25 °C) and is specified for unclamped inductive switching with E_AS = 25.9 mJ at T_j(init) = 25 °C - supporting reliable operation in relay replacement and H-bridge freewheeling applications.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	40 V maximum - supports full 12 V automotive battery transient margin (ISO 7637-2 Pulse 5a up to 40 V).
R_DS(on)	11–14 mΩ at V_GS = 5 V, I_D = 15 A, T_j = 25 °C - enables <1.5 W conduction loss at 30 A continuous current with proper thermal design.
I_D	44 A continuous at T_mb = 25 °C - usable up to 31 A at T_mb = 100 °C, matching under-hood ambient constraints.
Q_GD	4.8 nC - low gate-drain charge minimizes Miller-induced switching delay and improves hard-switching efficiency.
R_th(j-mb)	2.46 K/W typical - enables >40 W power dissipation with 100 °C mounting base temperature rise above ambient.
E_AS	25.9 mJ non-repetitive avalanche energy - allows safe clamping of inductive kickback without external snubbers in solenoid drivers.
V_GS(th)	≥0.5 V at T_j = 175 °C - ensures turn-on capability with standard 3.3 V/5 V microcontroller GPIOs even at peak junction temperature.

Pinout & Package

LFPAK33 (SOT1210) is a surface-mount plastic package with 8 leads and an exposed drain-connected mounting base (mb), optimized for low-inductance, high-current routing and direct thermal transfer to PCB copper.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3	Source (S)	Three parallel source terminals reduce bond-wire inductance and improve current sharing in high-di/dt switching.
4	Gate (G)	Single gate input with low input capacitance (C_iss = 911–1211 pF) for fast, low-power driving from MCU GPIOs.
mb	Mounting Base / Drain (D)	Exposed copper pad electrically connected to drain - serves as primary thermal path and high-current drain return.

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive-grade reliability including temperature cycling, humidity testing, and mechanical shock per JESD47.
Repetitive avalanche rating	Rated for repeated inductive energy clamping without degradation - eliminates need for external protection in motor commutation.
175 °C maximum junction temperature	Enables operation in under-hood environments (e.g., engine bay ECUs) without derating below 125 °C ambient.
True logic-level gate	V_GS(th) ≥ 0.5 V at 175 °C ensures guaranteed turn-on with 3.3 V or 5 V logic, reducing gate driver complexity.
Low R_DS(on) × Q_G figure-of-merit	11 mΩ × 11.3 nC = 124 mΩ·nC - balances conduction and switching losses for high-efficiency 10–100 kHz PWM loads.

Applications

Transmission Control Module

Lamp Driver Unit

Use Scenario: High-side switching of 12 V solenoids in automatic transmission valve bodies, operating continuously at 85 °C ambient.

IC Role / Device Role / Timing Role: Power switch controlling hydraulic pressure via PWM duty cycle (1–500 Hz), with integrated body diode enabling freewheeling.

Use Value: 14 mΩ R_DS(on) limits self-heating to <1.2 W at 30 A, while 175 °C rating avoids thermal shutdown during sustained gear shifts.

Use Scenario: Low-side switching of LED headlamps and fog lamps in vehicle lighting control modules.

IC Role / Device Role / Timing Role: Fast-switching load switch with 12.2 ns fall time, driven directly by 5 V microcontroller outputs.

Use Value: Q_GD = 4.8 nC and C_oss = 152–182 pF minimize switching losses during 100–500 Hz dimming, extending LED lifetime.

Engine Start-Stop System

Electric Power Steering (EPS) Assist Circuit

Use Scenario: Controlling starter motor engagement solenoid in 12 V start-stop systems with frequent cycling (up to 50,000 cycles).

IC Role / Device Role / Timing Role: High-current DC switch handling 44 A peak pulses, with avalanche energy absorption during coil de-energization.

Use Value: 25.9 mJ E_AS safely clamps inductive flyback without snubber components, reducing BOM count and board space.

Use Scenario: Driving 12 V brushed DC assist motors in EPS modules, subject to vibration, thermal cycling, and EMI.

IC Role / Device Role / Timing Role: Robust power stage component with AEC-Q101 qualification and 2.46 K/W thermal resistance for direct heatsink mounting.

Use Value: Junction-to-mounting-base thermal path enables stable 35 A continuous operation at 100 °C board temperature - meeting ISO 16750-4 requirements.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STL220N4F7AG	40 V, 2.2 mΩ R_DS(on), PowerFLAT 5x6 package, higher current but larger footprint and no AEC-Q101 certification.	Targeted at industrial motor drives; lacks automotive qualification and thermal performance validation for under-hood use.	Select only if higher current (>60 A) and lower R_DS(on) outweigh qualification and thermal packaging needs.
ON Semiconductor NTMFS4C09NT1G	40 V, 9.2 mΩ R_DS(on), SO-8FL package, AEC-Q101 qualified, but R_th(j-mb) = 3.5 K/W limits power handling.	Acceptable for lower-power lamp control, but insufficient thermal performance for sustained 30+ A solenoid loads.	Prefer for cost-sensitive, lower-current automotive lighting where thermal margin is less critical.

Compared with STL220N4F7AG and NTMFS4C09NT1G, the BUK9M14-40EX uniquely combines AEC-Q101 qualification, 2.46 K/W thermal resistance, and 0.5 V V_GS(th) at 175 °C - making it the only option validated for thermally aggressive, high-reliability 12 V automotive power switching with logic-level drive.

Availability

BUK9M14-40EX is available at Aetrix Electronics and suitable for automotive transmission control, engine start-stop systems, and electric power steering requiring stable component supply across extended production lifecycles.

Supply support for BUK9M14-40EX 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 and ESD protection.

The BUK9M series belongs to Nexperia's automotive logic-level MOSFET product line, engineered specifically for 12 V battery rail switching in harsh-environment automotive ECUs - emphasizing thermal robustness, avalanche safety, and AEC-Q101 compliance.

FAQ

Is BUK9M14-40EX pin-compatible with other LFPAK33 MOSFETs?

Yes - BUK9M14-40EX uses the standard SOT1210 footprint with identical pin assignment (Pins 1–3 = Source, Pin 4 = Gate, mounting base = Drain). It shares mechanical and solder-reflow compatibility with all Nexperia LFPAK33 logic-level MOSFETs, enabling drop-in substitution within the same voltage/current class.

What is the maximum continuous drain current at 100 °C mounting base temperature?

The datasheet specifies 31 A continuous drain current at T_mb = 100 °C and V_GS = 5 V. This value is derived from thermal derating curves (Figure 2) and accounts for junction temperature limits up to 175 °C, ensuring safe operation in under-hood environments.

Does BUK9M14-40EX require a gate resistor for automotive MCU drive?

A 5–10 Ω series gate resistor is recommended to dampen ringing and limit peak gate current when driven directly from 3.3 V or 5 V microcontrollers. The device's low Q_G (11.3 nC) and C_iss (911 pF) make it compatible with standard GPIOs, but external resistance improves EMI performance and gate drive stability.

Can BUK9M14-40EX replace older BUK9Yxx-75 series MOSFETs?

No - BUK9Yxx-75 devices are 75 V rated with different R_DS(on) and thermal characteristics. BUK9M14-40EX is strictly a 40 V part optimized for 12 V systems. Substitution requires verification of voltage margin, avalanche energy, and thermal interface compatibility - not a direct replacement.

BUK9M14-40EX Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: TrenchMOS™

Package/Case:: SOT-1210, 8-LFPAK33 (5-Lead)

Packaging:: Tape & Reel (TR)

Product Status:: Active

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 40 V

Current - Continuous Drain (Id) @ 25°C:: 44A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 5V

Rds On (Max) @ Id, Vgs:: 11mOhm @ 15A, 10V

Vgs(th) (Max) @ Id:: 2.1V @ 1mA

Gate Charge (Qg) (Max) @ Vgs:: 11.3 nC @ 5 V

Vgs (Max):: ±10V

Input Capacitance (Ciss) (Max) @ Vds:: 1211 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 55W (Tc)

Operating Temperature:: -55°C ~ 175°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: LFPAK33

BUK9M14-40EX FAQ

1.How can I place an order for BUK9M14-40EX through Aetrix?

Please submit a Request for Quotation (RFQ) for BUK9M14-40EX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BUK9M14-40EX reliable?

The price and inventory of BUK9M14-40EX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUK9M14-40EX is usually 5 days.

3.What payment methods are accepted for BUK9M14-40EX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUK9M14-40EX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUK9M14-40EX?

BUK9M14-40EX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUK9M14-40EX order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BUK9M14-40EX?

For technical support, including BUK9M14-40EX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUK9M14-40EX requirements.

6.How does Aetrix verify that BUK9M14-40EX is sourced from the original manufacturer or authorized distributors?

All BUK9M14-40EX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BUK9M14-40EX meets industry standards.

7.What is the process for return or replacement of BUK9M14-40EX?

All BUK9M14-40EX units undergo pre-shipment inspection (PSI). If there is an issue with BUK9M14-40EX, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BUK9M14-40EX part is unused and in its original packaging.

Return procedure for BUK9M14-40EX:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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