NXP Semiconductors BUK114-50L,118

Overview

BUK114-50L,118 from Philips Semiconductors is a monolithic temperature- and overload-protected logic-level power MOSFET in SOT426 (TO-263-5) surface-mount package, designed as a general-purpose automotive switch for lamps, motors, solenoids, and heaters. It features 50 V V_DS, 15 A continuous drain current at T_mb ≤ 25 °C, 125 mΩ R_DS(ON) at V_IS = 5 V, and integrated overvoltage clamping up to 65 V.

For engineers reviewing the BUK114-50L,118 datasheet, BUK114-50L,118 pinout, BUK114-50L,118 application, or BUK114-50L,118 equivalent, key selection criteria include its latched short-circuit protection with flag indication, separate 5 V protection supply pin, 5-pin SOT426 thermal performance (R_{th j-mb} = 2.5–3.1 K/W), and logic-compatible 1.0–2.0 V input threshold voltage.

Technical Context

The BUK114-50L,118 integrates a vertical DMOS output stage with dedicated logic and protection supply pins (V_PS = 5 V), enabling independent control of gate drive and protection circuitry. Its internal protection architecture includes dual-mode overload detection-overtemperature (T_j(TO) = 150 °C) and short-circuit (response time t_{d sc} = 375 µs)-with latched shutdown reset only via V_PS.

It supports both linear and switching operation, with overvoltage clamping activated above 50 V using an internal n-MOS transistor that discharges the gate capacitance. The open-drain flag pin provides real-time status (logic low = normal; logic high = overload or supply fault), requiring external pull-up (1–50 kΩ).

Key Specifications

Pinout & Package

SOT426 (TO-263-5) package with isolated mounting base (pin 3) electrically connected to drain; optimized for high-power surface-mount thermal management (R_{th j-mb} = 2.5–3.1 K/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar protected power switch applications.

Compared with STB120NF55 and BTS4140N, the BUK114-50L,118 delivers integrated latched protection and flag signaling in a compact 5-pin SOT426 package-offering faster time-to-market for cost-sensitive automotive and industrial switches where external protection complexity must be minimized.

Availability

BUK114-50L,118 is available at Aetrix Electronics and suitable for automotive lamp control, industrial solenoid actuation, and heater load management requiring stable component supply across extended production lifecycles.

Supply support for BUK114-50L,118 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

Philips Semiconductors (now NXP Semiconductors) is a global semiconductor innovator with leadership in automotive and industrial power management solutions.

The TOPFET product line was engineered specifically for robust, self-protected high-side switching in harsh automotive environments-emphasizing latchable fault handling, thermal resilience, and simplified system integration.

FAQ

What is the function of the flag pin on the BUK114-50L,118?

The flag pin on the BUK114-50L,118 is an open-drain output that signals operational status: logic low indicates normal operation with adequate protection supply voltage, while logic high indicates either overtemperature, short-circuit overload, or insufficient V_PS. It requires an external pull-up resistor (1–50 kΩ) and enables real-time fault reporting to microcontrollers without additional sensing circuitry. This feature is integral to the BUK114-50L,118's system-level reliability design.

Can the BUK114-50L,118 be used without connecting the protection supply pin?

No-the BUK114-50L,118 requires the protection supply pin (pin 4) to be connected to a stable 5 V source within 4.4–5.0 V for valid overload protection. Without this connection, overtemperature and short-circuit protection remain inactive, and the device operates without latched fault response. The BUK114-50L,118 datasheet explicitly states that V_PS < 4.4 V disables protection functionality, making it unsafe for automotive or industrial use cases requiring fail-safe behavior.

What is the maximum allowable drain-source voltage during inductive turn-off for the BUK114-50L,118?

The BUK114-50L,118 provides active overvoltage clamping above 50 V, with a typical clamping voltage of 65 V (V_(CL)DSR) under defined test conditions (R_IS = 100 Ω, I_D = 10 mA). During inductive turn-off, the device can safely absorb non-repetitive energy up to 200 mJ (E_DSM) without damage, provided external resistance limits peak current. This clamping behavior is a core safety feature built into the BUK114-50L,118's internal topology.

How does the BUK114-50L,118 handle thermal overload conditions?

The BUK114-50L,118 detects thermal overload via internal junction temperature sensing, triggering latched shutdown at T_j(TO) = 150 °C. Once tripped, the device remains off until the protection supply (V_PS) is cycled-ensuring persistent fault isolation. Thermal derating follows a defined curve: continuous drain current drops from 15 A at 25 °C to 9.5 A at 100 °C. This behavior is intrinsic to the BUK114-50L,118's monolithic protection architecture and is verified in its thermal characteristics table.

Is the BUK114-50L,118 pin-compatible with other TOPFET variants like BUK114-50S?

Yes-the BUK114-50L,118 shares identical pinout and package (SOT426) with BUK114-50S, differing only in nominal protection supply voltage (5 V vs. 10 V) and corresponding protection thresholds (e.g., V_PSP min = 4.4 V for BUK114-50L,118 vs. 5.4 V for BUK114-50S). Both variants use the same pin configuration, thermal footprint, and flag logic, enabling layout reuse across voltage-tiered designs. This compatibility is confirmed in Philips' official product specification document for BUK114-50L/S.