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

Nexperia USA Inc. BUK7Y29-40EX

Name: BUK7Y29-40EX
Brand: Nexperia USA Inc.
SKU: BUK7Y29-40EX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUK7Y29-40EX

Manufacturer:: Nexperia USA Inc.

Category:: FETs, MOSFETs

Package:: SC-100, SOT-669

Datasheet:: BUK7Y29-40EX.pdf

Description:: MOSFET N-CH 40V 26A LFPAK56

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Product details

Overview

BUK7Y29-40EX from Nexperia is a standard-level N-channel MOSFET in LFPAK56 (SOT669) package, rated for 40 V drain-source voltage, 29 mΩ R_DS(on) at V_GS = 10 V and T_j = 25 °C, and qualified to AEC-Q101 for automotive use. It delivers 26 A continuous drain current at T_mb = 25 °C and supports thermally demanding applications up to 175 °C junction temperature - deployed in 12 V automotive motor, lamp, and solenoid control circuits.

For engineers reviewing the BUK7Y29-40EX datasheet, BUK7Y29-40EX pinout, BUK7Y29-40EX application, or BUK7Y29-40EX equivalent, key selection criteria include its true standard-level gate (V_GS(th) > 1 V at 175 °C), repetitive avalanche rating, 4.03 K/W junction-to-mounting-base thermal resistance, and LFPAK56 package's high power density and PCB thermal relief capability.

Technical Context

This MOSFET uses TrenchMOS technology to achieve low on-resistance and fast switching with Q_GD = 3 nC and t_f = 5.1 ns under defined test conditions. Its gate threshold voltage remains functional across -55 °C to 175 °C, enabling robust operation in automotive engine bays and transmission control units.

The device integrates an intrinsic source-drain diode with V_SD = 0.85–1.2 V at I_S = 5 A and t_rr = 12 ns, supporting freewheeling in inductive loads. Its unclamped avalanche energy rating of 8.7 mJ (at I_D = 26 A, T_j(init) = 25 °C) provides design margin against transient overvoltage events.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	40 V - Maximum blocking voltage for 12 V automotive systems with load-dump transients.
R_DS(on)	22.7–29 mΩ @ V_GS = 10 V, I_D = 5 A, T_j = 25 °C - Enables low conduction loss in high-current switching paths.
I_D (continuous)	26 A @ T_mb = 25 °C - Supports high-power solenoid and motor drivers without external heatsinking.
P_tot	37 W @ T_mb = 25 °C - High power dissipation capacity enabled by LFPAK56 mounting base thermal path.
R_th(j-mb)	4.03 K/W - Low thermal resistance from junction to PCB copper mount, critical for sustained thermal performance.
V_GS(th)	> 1 V @ T_j = 175 °C - Ensures reliable turn-on with standard 5 V or 12 V gate drive in hot environments.
E_AS	8.7 mJ - Repetitive avalanche ruggedness allows safe operation during inductive kickback without snubbers.

Pinout & Package

LFPAK56 (SOT669) is a 4-lead plastic surface-mount package with exposed mounting base connected to drain, optimized for high-current automotive PCBs. Its footprint enables superior thermal transfer to copper pour versus SO-8 or DPAK.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3	Source (S)	Three parallel source terminals reduce package inductance and improve current sharing in high-di/dt switching.
4	Gate (G)	Single gate input with low Q_G(tot) = 7.9 nC - minimizes driver power and enables fast turn-on/turn-off.
Mounting Base	Drain (D)	Exposed copper pad electrically and thermally connected to drain - serves as primary heat path to PCB.

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD per JESD22.
Repetitive avalanche rated	Withstands repeated unclamped inductive switching events up to 8.7 mJ without degradation.
175 °C maximum junction temperature	Enables placement near heat sources (e.g., engine compartments) without derating or forced cooling.
True standard-level gate	V_GS(th) > 1 V at 175 °C ensures compatibility with legacy 5 V microcontroller GPIO and discrete logic drivers.
Low Q_GD/Q_G ratio	Q_GD = 3 nC / Q_G(tot) ≈ 38% - improves switching efficiency and reduces Miller-induced shoot-through risk.

Applications

Engine Cooling Fan Control

Automatic Transmission Solenoid Driver

Use Scenario: PWM-controlled 12 V DC brushless fan in engine bay with ambient temperatures up to 125 °C.

IC Role / Device Role / Timing Role: High-side or low-side power switch handling 15–20 A peak current with 20 kHz PWM frequency.

Use Value: 29 mΩ R_DS(on) and 4.03 K/W thermal resistance maintain T_j < 150 °C under full load, eliminating need for heatsink.

Use Scenario: Driving linear or on/off solenoids in 8-speed automatic transmission valve body.

IC Role / Device Role / Timing Role: Low-side switch controlling 12 V, 3–5 A solenoid coils with fast turn-off (<10 ns fall time) to prevent hydraulic lag.

Use Value: 5.1 ns fall time and 8.7 mJ avalanche rating absorb coil energy safely during rapid de-energization.

Headlamp LED Dimming Circuit

Start-Stop System Starter Relay Replacement

Use Scenario: High-current buck converter stage regulating 12 V supply to adaptive LED headlamps (up to 10 A).

IC Role / Device Role / Timing Role: Synchronous rectifier MOSFET operating in continuous conduction mode at 250 kHz.

Use Value: C_oss = 92–110 pF and Q_GD = 3 nC minimize switching losses and enable efficient zero-voltage switching behavior.

Use Scenario: Solid-state replacement for mechanical starter relay in vehicle start-stop systems with frequent cycling.

IC Role / Device Role / Timing Role: Main battery disconnect switch handling 200 A inrush and 50 A steady-state cranking current.

Use Value: 102 A peak drain current rating and 175 °C operation ensure reliability across 100,000+ cycles in high-temperature under-hood locations.

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, 175 °C rated, but gate threshold is 2.5–4.5 V (enhanced level).	Requires higher gate drive voltage; better for high-efficiency, low-loss designs where 3.3 V logic is unavailable.	Select when ultra-low R_DS(on) justifies redesign for enhanced-level gate drive and larger footprint.
ON Semiconductor NTMFS4C09NT1G	40 V, 3.2 mΩ R_DS(on), SO-8FL package, AEC-Q101 qualified, but max T_j = 150 °C and no avalanche rating.	Limited thermal margin in high-ambient environments; unsuitable for unclamped inductive switching.	Choose only for cost-sensitive, lower-power 12 V modules where ambient stays below 85 °C and no avalanche stress occurs.

Compared with STL220N4F7AG and NTMFS4C09NT1G, BUK7Y29-40EX offers the optimal balance of standard-level gate compatibility, 175 °C operation, and verified avalanche ruggedness - making it uniquely suited for thermally constrained, safety-critical automotive power stages without gate voltage upgrade.

Availability

BUK7Y29-40EX is available at Aetrix Electronics and suitable for automotive engine control units, transmission control modules, and ADAS power distribution systems requiring stable component supply across extended product lifecycles.

Supply support for BUK7Y29-40EX 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 essential semiconductors - delivering discrete, logic, and MOSFET solutions optimized for automotive, industrial, and mobile markets.

The BUK7Y series belongs to Nexperia's AEC-Q101-qualified standard-level automotive MOSFET portfolio, engineered specifically for robust, thermally resilient power switching in 12 V and 48 V vehicle subsystems.

FAQ

Is BUK7Y29-40EX suitable for high-frequency PWM motor control above 50 kHz?

Yes - with t_f = 5.1 ns, t_r = 5.5 ns, and Q_GD = 3 nC, BUK7Y29-40EX supports clean switching up to 200 kHz in low-inductance layouts. Its low C_oss (92–110 pF) and optimized gate charge profile minimize switching losses and EMI generation in BLDC gate-drive applications.

What is the maximum PCB copper area recommended for the mounting base to achieve rated P_tot = 37 W?

To achieve full 37 W power dissipation at T_mb = 25 °C, Nexperia specifies ≥ 1000 mm² of 2 oz copper connected directly to the mounting base via ≥ 4 thermal vias (0.3 mm diameter, filled). Smaller copper areas reduce P_tot proportionally per Fig. 2's derating curve.

Does BUK7Y29-40EX require a gate resistor for automotive solenoid driving?

A gate resistor of 4.7–10 Ω is recommended to damp ringing and limit peak gate current during fast transitions. This prevents overshoot beyond ±20 V V_GS rating while maintaining t_on/t_off within datasheet-specified ranges - especially critical when driving inductive loads with high dI/dt.

Can BUK7Y29-40EX replace older TO-220 or DPAK MOSFETs in existing automotive PCBs?

Yes - LFPAK56's 5.0 × 4.8 mm footprint is compatible with modified SO-8 land patterns and offers superior thermal performance vs. DPAK. However, the mounting base must be routed to drain potential, and source/gate layout must accommodate three parallel source pins instead of one - requiring minor PCB revision.

BUK7Y29-40EX Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: TrenchMOS™

Package/Case:: SC-100, SOT-669

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:: 26A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 10V

Rds On (Max) @ Id, Vgs:: 29mOhm @ 5A, 10V

Vgs(th) (Max) @ Id:: 4V @ 1mA

Gate Charge (Qg) (Max) @ Vgs:: 7.9 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 492 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 37W (Tc)

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

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: LFPAK56, Power-SO8

BUK7Y29-40EX FAQ

1.How can I place an order for BUK7Y29-40EX through Aetrix?

Please submit a Request for Quotation (RFQ) for BUK7Y29-40EX 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 BUK7Y29-40EX reliable?

The price and inventory of BUK7Y29-40EX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUK7Y29-40EX is usually 5 days.

3.What payment methods are accepted for BUK7Y29-40EX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUK7Y29-40EX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUK7Y29-40EX?

BUK7Y29-40EX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUK7Y29-40EX 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 BUK7Y29-40EX?

For technical support, including BUK7Y29-40EX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUK7Y29-40EX requirements.

6.How does Aetrix verify that BUK7Y29-40EX is sourced from the original manufacturer or authorized distributors?

All BUK7Y29-40EX 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 BUK7Y29-40EX meets industry standards.

7.What is the process for return or replacement of BUK7Y29-40EX?

All BUK7Y29-40EX units undergo pre-shipment inspection (PSI). If there is an issue with BUK7Y29-40EX, 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 BUK7Y29-40EX part is unused and in its original packaging.

Return procedure for BUK7Y29-40EX:

1.Submit a request within 90 days.

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

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