Nexperia USA Inc. PMST5551-QX

Overview

PMST5551-QX from Nexperia is an AEC-Q101-qualified NPN high-voltage transistor in SOT323 (SC-70) package, rated for 160 V V_CEO, 300 mA I_C, and 150 °C T_j, used as a switching element in automotive telephony and industrial HV signal conditioning circuits.

For engineers reviewing the PMST5551-QX datasheet, PMST5551-QX pinout, PMST5551-QX application, or PMST5551-QX equivalent, key selection criteria include its high-voltage capability (160 V), low-profile SMT package (2.0 × 1.25 × 0.95 mm), AEC-Q101 qualification, DC current gain range (30–250 at 50 mA), and thermal resistance (625 K/W on FR4).

Technical Context

This discrete NPN bipolar junction transistor operates in linear or saturated switching modes with V_CE(sat) ≤ 200 mV at I_C = 50 mA / I_B = 5 mA and exhibits f_T = 100 MHz at V_CE = 10 V / I_C = 10 mA. Its 180 V V_CBO rating supports robust collector-base isolation in high-side switch configurations.

Designed for stable performance across −65 °C to +150 °C ambient, it delivers low leakage (I_CBO ≤ 50 nA at 25 °C; ≤ 50 µA at 100 °C) and controlled capacitance (C_c = 6 pF, C_e = 30 pF), enabling predictable timing and noise behavior in analog and digital interface stages.

Key Specifications

Pinout & Package

Package: SOT323 (SC-70), plastic surface-mounted, 3-lead, 1.3 mm pitch, body dimensions 2.0 mm × 1.25 mm × 0.95 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage switching applications.

Compared with BC847BW and MMBT5551, the PMST5551-QX uniquely combines AEC-Q101 qualification, 160 V rating, and SOT323 form factor-making it the only drop-in solution for automotive HV switching where reliability and voltage headroom are jointly critical.

Availability

PMST5551-QX is available at Aetrix Electronics and suitable for automotive telephony interfaces, industrial HV signal switching, and LED driver stages requiring stable component supply and long-term lifecycle assurance.

Supply support for PMST5551-QX 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability essential semiconductors, with leadership in logic, discretes, and MOSFETs for automotive, industrial, and mobile markets.

The PMST5551-QX belongs to Nexperia's AEC-Q101-qualified high-voltage bipolar transistor family, engineered specifically for robust switching in automotive infotainment, body electronics, and industrial control systems operating up to 160 V.

FAQ

Is PMST5551-QX pin-compatible with MMBT5551?

Yes-both use identical SOT323 (SC-70) pinning: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. Mechanical and electrical pin mapping is fully compatible, enabling direct PCB replacement where qualification and thermal limits permit.

What is the maximum allowable pulsed collector current?

The peak collector current (I_CM) is specified at 600 mA under pulsed conditions (duty cycle ≤ 2%, pulse width ≤ 300 µs). This supports short-duration surge handling in relay coil kickback suppression or transient load switching.

Does PMST5551-QX support wave soldering?

Yes-Nexperia provides a dedicated wave soldering footprint (Fig. 4) with 3.65 mm × 2.1 mm solder land pattern and preferred transport direction alignment. Reflow profile compliance is also verified per J-STD-020.

How does the 625 K/W thermal resistance impact design?

At 200 mW total power dissipation and 25 °C ambient, junction temperature reaches 150 °C-the absolute maximum. Designers must limit average power to ≤120 mW on standard FR4 to maintain 25 °C safety margin, or use thermal vias for enhanced cooling.