NXP Semiconductors BUK9E1R8-40E,127

Overview

BUK9E1R8-40E from NXP Semiconductors is an AEC-Q101-qualified N-channel TrenchMOS logic-level power MOSFET in I2PAK (SOT226) package, rated for 40 V V_DS, 120 A continuous drain current at T_mb = 25 °C, and 1.55 mΩ typical R_DS(on) at V_GS = 5 V and T_j = 25 °C. It serves as a high-current, thermally robust switching element in automotive 12 V systems including start-stop micro-hybrid control and transmission actuation.

For engineers reviewing the BUK9E1R8-40E datasheet, BUK9E1R8-40E pinout, BUK9E1R8-40E application, or BUK9E1R8-40E equivalent, key selection considerations include its true logic-level gate (V_GS(th) ≥ 0.5 V at 175 °C), 175 °C junction rating, repetitive avalanche capability, and mounting-base thermal resistance of 0.43 K/W - critical for high-power automotive thermal design.

Technical Context

This MOSFET employs NXP's TrenchMOS technology to achieve low on-resistance with logic-level gate drive compatibility. Its gate threshold voltage remains functional up to 175 °C, enabling reliable operation in under-hood environments without external level-shifting circuitry. The device integrates a source-drain diode with 57 ns reverse recovery time and 97 nC recovered charge, supporting synchronous rectification and freewheeling in inductive loads.

The I2PAK (SOT226) package features a drain-connected mounting base for direct heatsinking, delivering 349 W total power dissipation at T_mb = 25 °C. Its safe operating area supports pulsed peak drain currents up to 1257 A (tp ≤ 10 µs), and it is rated for non-repetitive avalanche energy of 1008 mJ under unclamped conditions.

Key Specifications

Pinout & Package

The BUK9E1R8-40E is housed in an I2PAK (SOT226) plastic single-ended package with a drain-connected mounting base for low-thermal-resistance heatsinking. The package outline conforms to TO-262 mechanical standards and features three leads plus a metal mounting base electrically tied to the drain terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STL220N4F7AG and NTMFS4C09NT1G, the BUK9E1R8-40E uniquely combines AEC-Q101 qualification, true 5 V logic-level operation at 175 °C, and I2PAK thermal performance - making it the only option among the three validated for high-power, high-temperature automotive switching where reliability and thermal margin are non-negotiable.

Availability

BUK9E1R8-40E is available at Aetrix Electronics and suitable for automotive power distribution, start-stop micro-hybrid systems, and transmission control applications requiring stable component supply across extended production lifecycles.

Supply support for BUK9E1R8-40E 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.

The BUK9E1R8-40E belongs to NXP's TrenchMOS logic-level automotive power MOSFET family, engineered specifically for high-current, high-temperature 12 V automotive subsystems where AEC-Q101 reliability and thermal resilience are essential.

FAQ

What is the maximum continuous drain current rating for BUK9E1R8-40E?

The BUK9E1R8-40E has a maximum continuous drain current of 120 A at mounting base temperature (T_mb) = 25 °C, as specified in Table 1 and Table 4 of the datasheet. This rating is package-limited and decreases with rising T_mb, reaching zero at T_mb ≈ 175 °C. At T_mb = 100 °C, the continuous current remains 120 A due to thermal derating characteristics shown in Figure 1. The BUK9E1R8-40E maintains this rating under strict thermal management using its drain-connected mounting base.

Is BUK9E1R8-40E suitable for 5 V microcontroller gate drive?

Yes, the BUK9E1R8-40E is explicitly designed as a logic-level MOSFET with guaranteed turn-on at 5 V. Its gate-source threshold voltage V_GS(th) is ≥ 0.5 V at T_j = 175 °C, ensuring robust enhancement-mode operation with standard 5 V digital outputs. The typical R_DS(on) of 1.55 mΩ at V_GS = 5 V confirms full enhancement at this voltage, making the BUK9E1R8-40E compatible with automotive MCUs such as S32K series without external level shifters.

What is the thermal resistance from junction to mounting base for BUK9E1R8-40E?

The maximum thermal resistance from junction to mounting base (R_th(j-mb)) for the BUK9E1R8-40E is 0.43 K/W, as stated in Table 5. This low value reflects the direct thermal path through the drain-connected mounting base in the I2PAK (SOT226) package. When mounted to a properly sized heatsink, this enables the BUK9E1R8-40E to dissipate up to 349 W at T_mb = 25 °C - a key advantage over surface-mount alternatives in high-power automotive applications.

Does BUK9E1R8-40E have avalanche capability?

Yes, the BUK9E1R8-40E is rated for both non-repetitive and repetitive avalanche operation. Its non-repetitive drain-source avalanche energy (E_AS) is 1008 mJ under unclamped inductive switching conditions (ID = 120 A, V_sup ≤ 40 V). The datasheet also confirms repetitive avalanche rating in Figure 3. This ruggedness eliminates the need for external avalanche clamps in motor, solenoid, and lamp driving applications where inductive kickback is routine - a core design feature of the BUK9E1R8-40E.

What automotive qualification does BUK9E1R8-40E meet?

The BUK9E1R8-40E is qualified to AEC-Q101 standard for discrete semiconductors, as explicitly stated in Section 1.1 and 1.2 of the product data sheet. This qualification covers stress tests including high-temperature operating life (HTOL), temperature cycling, humidity bias HAST, and mechanical shock/vibration - validating its suitability for under-hood and safety-critical automotive subsystems. The BUK9E1R8-40E is not merely "designed for" automotive use; it is formally certified to AEC-Q101 Rev D requirements.