NXP Semiconductors PHM21NQ15T,518

Overview

PHM21NQ15T from Philips Semiconductors is an N-channel enhancement-mode TrenchMOS™ power MOSFET in QLPAK (SOT685-1) package, rated for 150 V V_DS, 22.2 A continuous drain current at T_mb = 25 °C, and 55 mΩ maximum R_DS(on) at V_GS = 10 V and T_j = 25 °C. It serves as a primary-side switching device in DC-to-DC converters for portable equipment.

For engineers reviewing the PHM21NQ15T datasheet, PHM21NQ15T pinout, PHM21NQ15T application, or PHM21NQ15T equivalent, key selection criteria include avalanche energy rating (250 mJ non-repetitive), thermal resistance (2 K/W junction-to-mounting-base), gate charge (36.2 nC total), and SOT685-1 surface-mount compatibility with low-profile thermal-enhanced layout.

Technical Context

This device uses TrenchMOS™ technology to achieve low R_DS(on) and high avalanche ruggedness. Its gate threshold voltage ranges from 2–4 V at 25 °C and remains functional down to −55 °C (max 4.4 V) and up to 150 °C (min 1.2 V), supporting stable turn-on across industrial temperature extremes.

The source-drain body diode exhibits 0.83–1.2 V forward voltage at 10 A and 150 ns reverse recovery time, enabling synchronous rectification support in flyback and resonant topologies. Dynamic parameters-including 11.6 nC Miller charge and 90 pF reverse transfer capacitance-support high-frequency switching up to several hundred kHz with controlled EMI.

Key Specifications

Pinout & Package

Package: QLPAK (SOT685-1), plastic thermal-enhanced very thin small outline package; no leads; 8 terminals; body 6 × 5 × 0.85 mm; mounting base electrically connected to drain.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP22NF15 and IRF6644, the PHM21NQ15T offers superior thermal performance via its QLPAK mounting base (2 K/W vs. >60 K/W), making it uniquely suited for compact, thermally demanding DC-DC primary-side roles where board area and heatsink volume are constrained.

Availability

PHM21NQ15T is available at Aetrix Electronics and suitable for DC-DC converters, portable power supplies, and industrial 48 V input systems requiring stable component supply and long-term manufacturability.

Supply support for PHM21NQ15T 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 Dutch semiconductor pioneer known for power management, RF, and automotive ICs, with deep expertise in discrete power devices.

The PHM21NQ15T belongs to Philips' TrenchMOS™ standard-level FET product line, engineered specifically for high-current, medium-voltage primary-side switching in compact, thermally constrained offline and DC-DC power supplies.

FAQ

What is the maximum continuous drain current rating for PHM21NQ15T at elevated temperatures?

The PHM21NQ15T supports 22.2 A continuous drain current at mounting base temperature (T_mb) = 25 °C and 14 A at T_mb = 100 °C, per Figure 2 in the datasheet. Derating follows the normalized curve in Figure 2, with full current capability maintained only when thermal design ensures T_mb stays ≤100 °C. The PHM21NQ15T's 2 K/W R_th(j-mb) enables this performance with proper PCB copper area.

Does PHM21NQ15T have avalanche capability, and how is it specified?

Yes, the PHM21NQ15T is rated for non-repetitive drain-source avalanche energy of 250 mJ under defined conditions (ID = 12 A, tp = 0.21 ms, VDD ≤150 V, RGS = 50 Ω, VGS = 10 V, starting Tj = 25 °C). It also specifies 2.5 mJ repetitive avalanche energy. These values are absolute limiting ratings-not recommended for routine operation-but confirm ruggedness against transient overvoltage events. The PHM21NQ15T's avalanche performance is validated per IEC 60134 guidelines.

What is the gate threshold voltage range for PHM21NQ15T across temperature?

The PHM21NQ15T gate-source threshold voltage (V_GS(th)) is specified from 2–4 V at T_j = 25 °C, 1.2–? V at 150 °C (min 1.2 V), and up to 4.4 V at −55 °C. This wide operational window ensures reliable turn-on with standard 5 V or 10 V gate drivers across industrial temperature ranges. The PHM21NQ15T maintains usable gate control even at extreme cold or hot junction conditions.

How does the QLPAK package of PHM21NQ15T improve thermal performance compared to SO-8?

The PHM21NQ15T's QLPAK (SOT685-1) package features an exposed mounting base electrically tied to the drain, delivering a junction-to-mounting-base thermal resistance of just 2 K/W-significantly lower than typical SO-8 packages (>50 K/W). This allows direct thermal coupling to PCB copper pours or heatsinks, enabling >60 W power dissipation without external heatsinks. The PHM21NQ15T leverages this for compact, high-power-density designs.

Can PHM21NQ15T be used as a synchronous rectifier, and what body diode characteristics support that role?

Yes, the PHM21NQ15T can serve as a synchronous rectifier due to its integrated source-drain body diode, characterized with V_SD = 0.83–1.2 V at IS = 10 A and reverse recovery time t_rr = 150 ns. Its recovered charge Q_r is 215 nC, enabling moderate-frequency (<300 kHz) synchronous operation with manageable switching loss. While not optimized for ultra-fast recovery like dedicated SR FETs, the PHM21NQ15T's diode parameters support cost-effective dual-role use in flyback and forward converters.