NXP Semiconductors PMST5401,135

Overview

PMST5401 from NXP Semiconductors (formerly Philips) is a PNP high-voltage general-purpose transistor in SOT323 package, rated for −150 V V_CEO, −300 mA I_C, and 200 mW P_tot, used in telephony line interface circuits and low-power switching applications.

For engineers reviewing the PMST5401 datasheet, PMST5401 pinout, PMST5401 application, or PMST5401 equivalent, this page delivers verified electrical parameters, thermal resistance (625 K/W), transition frequency (100–300 MHz), noise figure (≤8 dB), and SOT323 terminal mapping to support circuit design, BOM validation, and replacement analysis.

Technical Context

The PMST5401 operates as a medium-speed PNP bipolar junction transistor with DC current gain (h_FE) ranging from 50 to 240 depending on collector current (−1 mA to −50 mA), and exhibits low saturation voltages (V_CEsat ≤ −500 mV at I_C = −50 mA / I_B = −5 mA).

It features low collector capacitance (C_c ≤ 6 pF), high transition frequency (f_T ≥ 100 MHz), and low noise figure (≤8 dB at 10 Hz–15.7 kHz), making it suitable for analog signal amplification and switching in space-constrained telephony and industrial control modules.

Key Specifications

Pinout & Package

SOT323 (SC-70) plastic surface-mount package: 3-lead, 1.35 mm × 1.15 mm footprint, 0.65 mm pitch, 0.23 mm max height - compatible with standard 0.5 mm stencil apertures and reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage transistor applications.

Compared with BC807-40,115 and MMBT5401, the PMST5401 uniquely balances −150 V blocking capability with low-noise audio performance and compact SOT323 packaging - critical for space- and voltage-sensitive telephony designs where MMBT5401 offers sourcing flexibility and BC807-40,115 trades voltage headroom for current capacity.

Availability

PMST5401 is available at Aetrix Electronics and suitable for telephony infrastructure, industrial I/O modules, and analog audio signal conditioning requiring stable component supply and long-term obsolescence management.

Supply support for PMST5401 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 is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' pioneering discrete device development.

The PMST5401 belongs to NXP's legacy high-voltage bipolar transistor family, designed specifically for reliability-critical analog and switching functions in telecom and industrial equipment where voltage margin and thermal stability are essential.

FAQ

What is the maximum collector-emitter voltage rating for the PMST5401?

The PMST5401 has a maximum collector-emitter voltage (V_CEO) rating of −150 V under open-base conditions. This rating is confirmed in the Absolute Maximum Ratings table and allows safe operation in −48 V telecom systems with substantial transient margin. Exceeding −150 V risks permanent breakdown. The PMST5401 must be operated within this limit in all designs.

Is the PMST5401 pin-compatible with the MMBT5401?

Yes, the PMST5401 is pin-compatible with the MMBT5401: both use SOT323 package with identical pin 1 (base), pin 2 (emitter), pin 3 (collector) assignment and mechanical dimensions. Electrical specifications match per datasheet cross-reference, enabling direct substitution without PCB changes. The PMST5401 and MMBT5401 share identical marking "2L" and thermal characteristics.

What is the typical DC current gain (h_FE) of the PMST5401 at −10 mA collector current?

The PMST5401 exhibits a typical DC current gain (h_FE) of 60–240 at I_C = −10 mA and V_CE = −5 V, as specified in the Characteristics table. This range reflects process variation; designs requiring stable gain should include emitter degeneration or closed-loop biasing. The PMST5401's h_FE remains usable down to −1 mA and up to −50 mA, with minimum 50 guaranteed at extremes.

Can the PMST5401 be used in audio amplifier applications?

Yes, the PMST5401 is suitable for low-noise audio preamplifier stages due to its ≤8 dB noise figure (measured 10 Hz–15.7 kHz), 100–300 MHz f_T, and low 6 pF collector capacitance. It maintains linearity in common-emitter configuration at voice-band frequencies. The PMST5401's performance is validated in telephony signal paths, confirming suitability for analog audio where voltage headroom and SNR matter.

What is the thermal resistance from junction to ambient for the PMST5401?

The PMST5401 has a thermal resistance from junction to ambient (R_{th j-a}) of 625 K/W when mounted on a standard FR4 printed-circuit board, as stated in the Thermal Characteristics section. This value assumes no copper pour or thermal vias; adding 1 cm² of 2-oz copper on the collector pad can reduce R_{th j-a} by ~200 K/W. The PMST5401's 200 mW P_tot rating is directly derived from this thermal resistance at 25 °C ambient.