NXP Semiconductors BUK9518-55,127

Overview

BUK9518-55,127 from NXP Semiconductors (formerly Philips) is an N-channel enhancement-mode logic-level TrenchMOS™ power transistor in TO220AB package, featuring 55 V V_DS, 57 A I_D (DC), 18 mΩ R_DS(ON) at V_GS = 5 V, 125 W P_tot, and integrated ESD protection up to 2 kV. It serves as a high-current, low-loss switching element in automotive load control and industrial DC power distribution.

For engineers reviewing the BUK9518-55,127 datasheet, BUK9518-55,127 pinout, BUK9518-55,127 application, or BUK9518-55,127 equivalent, this page delivers verified electrical parameters, thermal behavior at mounting base, gate drive compatibility with 5 V logic, and validated alternatives for automotive-grade high-side/low-side switching designs.

Technical Context

The BUK9518-55,127 uses trench-gate MOSFET technology to achieve low R_DS(ON) while maintaining robust avalanche capability (125 mJ unclamped) and fast switching (t_d(on) ≤ 45 ns, t_f ≤ 75 ns). Its gate threshold voltage ranges from 1.0–2.0 V at 25 °C, enabling reliable turn-on with standard 5 V microcontroller outputs.

Thermal performance is defined by R_{th j-mb} ≤ 1.2 K/W junction-to-mounting-base, supporting high-power operation when heatsinked. The device includes an intrinsic body diode with V_SD = 0.95–1.2 V at 25 A and t_rr = 48 ns, suitable for freewheeling and synchronous rectification in DC-DC converters.

Key Specifications

Pinout & Package

Package: TO220AB (SOT78), plastic envelope with metal tab electrically connected to drain; net mass 2 g; UL94 V0 compliant epoxy.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP55NF06L and IRFZ44NPBF, the BUK9518-55,127 offers optimal balance of 5 V logic compatibility, 18 mΩ conduction loss, and 125 mJ avalanche ruggedness-making it preferred for automotive and industrial switching where reliability under transient stress is non-negotiable.

Availability

BUK9518-55,127 is available at Aetrix Electronics and suitable for automotive body electronics, industrial motor control, and 48 V telecom power distribution requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for BUK9518-55,127 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, headquartered in Eindhoven, Netherlands, develops high-reliability semiconductor solutions for automotive, industrial, and IoT markets with emphasis on functional safety and AEC-Q101 qualification.

The BUK9518-55,127 belongs to NXP's TrenchMOS™ logic-level power MOSFET family, engineered specifically for robust, low-voltage gate-driven switching in harsh automotive and industrial environments where ESD resilience and avalanche energy handling are critical.

FAQ

What is the maximum continuous drain current for BUK9518-55,127 at 100 °C mounting base temperature?

The BUK9518-55,127 supports 40 A continuous drain current (I_D) at T_mb = 100 °C, as specified in the Limiting Values table. This derating from 57 A at 25 °C reflects thermal constraints of the TO220AB package and must be respected in thermal design to avoid exceeding 175 °C junction temperature. The BUK9518-55,127 datasheet provides normalized current derating curves confirming this linear reduction.

Is BUK9518-55,127 suitable for high-side switching configurations?

Yes, the BUK9518-55,127 can be used in high-side configurations, but gate drive must be referenced to the source terminal-requiring a floating or bootstrap gate driver capable of delivering ≥5 V above the drain rail. Its logic-level V_GS(th) (1.0–2.0 V) simplifies gate biasing, though the 10 V absolute maximum V_GS limits overdrive margin. The BUK9518-55,127's drain-connected tab necessitates electrical isolation from the heatsink in such topologies.

Does BUK9518-55,127 have a built-in body diode, and what are its key characteristics?

Yes, the BUK9518-55,127 integrates a parasitic body diode with V_SD = 0.95–1.2 V at 25 A and reverse recovery time t_rr = 48 ns. This diode supports freewheeling in inductive loads and enables bidirectional current flow in battery disconnect applications. Its Q_rr is 0.1 µC, minimizing recovery losses in high-frequency switching. The BUK9518-55,127 datasheet confirms these values under specified test conditions (IF = 50 A, -dIF/dt = 100 A/µs).

What is the thermal resistance from junction to mounting base for BUK9518-55,127?

The BUK9518-55,127 has a maximum thermal resistance of R_{th j-mb} = 1.2 K/W from junction to mounting base, measured with proper mechanical mounting per TO220AB guidelines. This value assumes direct metal-to-metal contact with thermal compound and is critical for calculating junction temperature rise: T_j = T_mb + (P_diss × R_{th j-mb}). The BUK9518-55,127 datasheet specifies this parameter in the Thermal Resistances section.

Can BUK9518-55,127 replace older Philips BUK95xx-55 series parts in existing designs?

Yes, the BUK9518-55,127 is a direct replacement for earlier versions in the BUK95xx-55 family (e.g., BUK9518-55,118) with identical pinout, package, and electrical specifications. NXP maintains backward compatibility across date codes and ordering variants within the same part number suffix group. The BUK9518-55,127 shares identical limiting values, static/dynamic characteristics, and mechanical dimensions per the April 1998 product specification.