Nexperia USA Inc. BSR31-QX

Overview

BSR31-QX from Nexperia is a PNP medium-power bipolar junction transistor in SOT89 package, rated for −60 V V_CEO, −1 A continuous collector current, and 1.35 W power dissipation at T_amb ≤ 25 °C. It serves as a high-side switch or linear regulator pass element in automotive battery-driven systems, with AEC-Q101 qualification and exposed heatsink for thermal management.

For engineers reviewing the BSR31-QX datasheet, BSR31-QX pinout, BSR31-QX application, or BSR31-QX equivalent, key selection criteria include verified PNP polarity, −60 V breakdown rating, DC current gain (h_FE = 100–300 at −100 mA), thermal resistance (R_th(j-sp) = 13 K/W), and SOT89 mechanical compatibility with FR4 PCB mounting.

Technical Context

This device operates as a single PNP BJT with fixed emitter-base-collector terminal assignment and no integrated biasing or protection circuitry. Its design centers on robust linear-mode operation under pulsed and DC conditions, supported by specified saturation voltages (V_CEsat ≤ −0.5 V at −500 mA/−50 mA) and transition frequency (f_T = 100 MHz).

Thermal performance relies on the exposed collector pad in the SOT89 package, enabling low R_th(j-sp) = 13 K/W to solder point and qualifying it for automotive ambient ranges (−65 °C to +150 °C). Electrical limits strictly follow IEC 60134 absolute maximum ratings, including −70 V V_CBO and −5 V V_EBO.

Key Specifications

Pinout & Package

SOT89 plastic surface-mount package with 3 leads, 1.5 mm pitch, 4.5 mm × 2.5 mm × 1.5 mm body, and exposed collector pad for thermal and electrical conduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power transistor applications.

Compared with BSR41-Q and MMBT3906LT1G, the BSR31-QX delivers automotive-grade reliability, higher current capability, and superior thermal performance in high-side configurations-making it uniquely suited for 12 V/24 V battery systems requiring robustness and board-level heat sinking.

Availability

BSR31-QX is available at Aetrix Electronics and suitable for linear voltage regulators, high-side switches, and battery-driven devices requiring stable component supply, AEC-Q101 compliance, and SOT89 thermal performance.

Supply support for BSR31-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 essential efficiency technologies, delivering high-performance, reliable discrete and logic devices for automotive, industrial, and consumer markets.

The BSR31-QX belongs to Nexperia's AEC-Q101-qualified medium-power bipolar transistor product line, engineered specifically for automotive power management and load switching where thermal robustness and transient tolerance are critical.

FAQ

Is BSR31-QX pin-compatible with other SOT89 PNP transistors?

Yes-BSR31-QX follows standard SOT89 pinout (1 = E, 2 = C, 3 = B) and mechanical dimensions (4.5 mm × 2.5 mm × 1.5 mm). It matches industry-standard SOT89 footprints used by ON Semiconductor, Diodes Inc., and STMicroelectronics PNP devices, provided thermal pad layout aligns with Nexperia's 6 cm² recommendation.

What is the maximum safe operating temperature for BSR31-QX in continuous use?

The junction temperature must not exceed 150 °C. At ambient temperatures up to 105 °C (typical under-hood), continuous I_C must be derated using the R_th(j-a) = 93 K/W curve or R_th(j-sp) = 13 K/W with proper PCB copper area. Full 1 A current is only permissible below ~60 °C ambient with adequate heatsinking.

Does BSR31-QX require external base current limiting in switching applications?

Yes-base current must be limited to prevent exceeding I_BM = −200 mA peak. For I_C = −1 A and h_FE = 100, minimum I_B = −10 mA is required; typical designs use 1–10 kΩ series resistors from microcontroller GPIO to base, depending on drive voltage and switching speed requirements.

Can BSR31-QX replace BSR31 in existing designs?

Yes-BSR31-QX is the qualified automotive-grade version of BSR31, sharing identical electrical specs, pinout, and package. The "-QX" suffix denotes AEC-Q101 qualification and enhanced process controls; it is backward compatible and recommended for new automotive designs where reliability validation is mandatory.