NXP Semiconductors PHB55N03LTA,118

Overview

PHB55N03LTA from NXP Semiconductors (formerly Philips) is an N-channel logic-level TrenchMOS™ power MOSFET in SOT404 (D2-PAK) package, rated for 25 V V_DS, 55 A I_D (DC at T_mb = 25 °C), and 11–14 mΩ R_DS(on) at V_GS = 10 V, designed for high-frequency DC–DC converters on computer motherboards.

For engineers reviewing the PHB55N03LTA datasheet, PHB55N03LTA pinout, PHB55N03LTA application, or PHB55N03LTA equivalent, this page delivers verified electrical specs, thermal resistance (R_th(j-mb) = 1.75 K/W), gate charge (Q_g(tot) = 20 nC), avalanche energy (60 mJ), and mounting-base–referenced derating curves - all critical for synchronous buck stage design and thermal layout validation.

Technical Context

This logic-level MOSFET uses TrenchMOS™ technology to achieve low R_DS(on) with gate threshold voltage V_GS(th) of 1.0–2.0 V (typ. 1.5 V) and fast switching enabled by Q_gd = 7 nC and t_f = 40–60 ns. It supports operation up to T_j = 175 °C with guaranteed avalanche ruggedness under unclamped inductive load conditions.

The device integrates a source-drain diode with V_SD = 0.95–1.2 V at I_S = 25 A and ISM = 220 A peak, and features ±20 V gate-source voltage rating and 25 V drain-gate voltage limit - enabling robust gate drive and safe operation in high-side or low-side configurations with moderate bus voltages.

Key Specifications

Pinout & Package

SOT404 (D2-PAK) plastic surface-mount package with isolated mounting base connected internally to drain (pin 2); pin 2 is not accessible for external connection per datasheet note [1]. Mounting base serves as primary thermal path and high-current drain node.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP55NF03L and IRF3710ZPBF, PHB55N03LTA offers superior thermal performance via SOT404 mounting base, lower R_DS(on), and documented 60 mJ avalanche ruggedness - making it the preferred choice for high-density, high-reliability motherboard and server VRM designs.

Availability

PHB55N03LTA is available at Aetrix Electronics and suitable for computer motherboard VRMs, server CPU power delivery, and industrial PLC power supplies requiring stable component supply, long-lifecycle support, and traceable sourcing for production programs.

Supply support for PHB55N03LTA 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, formerly Philips Semiconductors, is a global leader in high-performance analog and power semiconductor solutions, with deep expertise in automotive, industrial, and computing power management.

The PHB55N03LTA belongs to the TrenchMOS™ Logic Level FET product line, engineered specifically for high-efficiency, high-current DC–DC conversion in space-constrained computing and server platforms where logic-level drive and thermal performance are critical.

FAQ

What is the maximum continuous drain current for PHB55N03LTA at 100 °C mounting base temperature?

The PHB55N03LTA supports 38 A continuous drain current at T_mb = 100 °C, as specified in Table 3 (Limiting Values) of the datasheet. This derated value reflects thermal constraints when ambient or heatsink conditions elevate mounting base temperature beyond 25 °C, and must be applied in thermal design calculations alongside R_th(j-mb) = 1.75 K/W.

Does PHB55N03LTA have a built-in body diode, and what is its forward voltage?

Yes, PHB55N03LTA includes an integrated source-drain body diode with V_SD = 0.95–1.2 V at I_S = 25 A and V_GS = 0 V (Table 5, Characteristics). This diode enables synchronous rectification or freewheeling operation in buck and flyback topologies without external components.

Can PHB55N03LTA be driven directly by a 3.3 V microcontroller GPIO?

Yes - PHB55N03LTA has a logic-level gate threshold (V_GS(th) = 1.0–2.0 V typ.) and achieves R_DS(on) ≤ 18 mΩ at V_GS = 5 V. At 3.3 V, it operates in enhanced mode but with higher R_DS(on); full 55 A rating requires ≥4.5 V gate drive, so 3.3 V use is viable only in low-current or thermally relaxed applications.

What is the thermal resistance from junction to mounting base for PHB55N03LTA?

The PHB55N03LTA has a thermal resistance R_th(j-mb) of 1.75 K/W, measured from silicon junction to the mounting base (Table 4, Thermal Characteristics). This value assumes proper soldering to a thermally optimized PCB pad or external heatsink and is the dominant thermal path for heat removal.

Is PHB55N03LTA pin-compatible with PHD55N03LTA or PHP55N03LTA?

No - PHB55N03LTA (SOT404/D2-PAK), PHD55N03LTA (SOT428/D-PAK), and PHP55N03LTA (SOT78/TO-220AB) share identical electrical specifications but differ in package outline, pin pitch, mounting method, and thermal interface. Their pin numbering is identical (G-D-S), but mechanical fit and PCB footprint are not interchangeable.