Diodes Incorporated BSR31TA

Overview

BSR31TA from Nexperia is a PNP silicon planar medium-power transistor in SOT89 package, rated for V_CEO = −60 V, I_C = −1 A, P_TOT = 1 W at T_amb = 25°C, with h_FE = 30–100 at I_C = −100 µA and V_CE = −5 V. It serves as a medium-current switch or linear amplifier in DC-DC converter bias networks, relay drivers, and LED current sinks.

For engineers reviewing the BSR31TA datasheet, BSR31TA pinout, BSR31TA application, or BSR31TA equivalent, key selection criteria include verified V_CEO rating, guaranteed h_FE range at low and medium I_C, SOT89 thermal performance under pulsed load, and complementary pairing with BSR41 for push-pull stages.

Technical Context

The BSR31TA operates as a medium-power PNP bipolar junction transistor with planar epitaxial construction, optimized for stable DC and low-frequency switching up to 100 kHz. Its breakdown ratings (V_CBO = −70 V, V_CEO = −60 V) support use in 48 V rail interfaces and industrial control logic where reverse polarity protection is required.

Electrical behavior is characterized by V_CE(sat) ≤ −0.25 V at I_C = −150 mA / I_B = −15 mA and f_T = 100 MHz at I_C = −50 mA / V_CE = −10 V, confirming suitability for both saturated switching and moderate-gain analog amplification in temperature-stable designs.

Key Specifications

Pinout & Package

SOT89 package: 3-pin surface-mount plastic case with exposed emitter pad for thermal conduction; pin 1 = Emitter, pin 2 = Base, pin 3 = Collector (viewed top-down, tab side left).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC807-40 and ZTX753, the BSR31TA uniquely balances SMT manufacturability, 1 W power handling, and −60 V V_CEO in a thermally enhanced SOT89 package-making it optimal for industrial 48 V systems requiring reliability and board-level thermal management.

Availability

BSR31TA is available at Aetrix Electronics and suitable for industrial relay drivers, 48 V DC-DC bias control, LED current sinks, and push-pull output stages requiring stable component supply and long-term production continuity.

Supply support for BSR31TA 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 discrete and logic devices, with leadership in automotive-qualified components and efficient manufacturing.

The BSR31TA belongs to Nexperia's medium-power bipolar transistor family, engineered for robust operation in industrial power management and interface circuits where thermal stability and voltage margin are critical.

FAQ

Is BSR31TA RoHS compliant and halogen-free?

Yes, BSR31TA meets RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. The device carries Nexperia's standard green marking and complies with JEDEC J-STD-020 moisture sensitivity level MSL3, requiring bake prior to reflow if exposed beyond floor life.

What is the maximum allowable junction temperature during continuous operation?

The BSR31TA has a maximum junction temperature (T_j) of +150°C. At T_amb = 25°C and P_TOT = 1 W, junction-to-ambient thermal resistance (R_θJA) is approximately 150 K/W, so sustained operation at full power requires ≥1 cm² of 2-oz copper on the emitter pad to maintain T_j ≤ 125°C.

Can BSR31TA be used in linear amplifier configurations?

Yes, BSR31TA supports linear operation with verified h_FE = 50–100 at I_C = −100 mA and V_CE = −5 V. Its f_T = 100 MHz and low C_c = 20 pF enable stable small-signal amplification up to ~10 MHz, provided V_CE remains within −5 V to −30 V and power dissipation stays below derated limits.

How does BSR31TA differ from its complementary NPN counterpart BSR41?

BSR31TA (PNP) and BSR41 (NPN) share identical SOT89 package, voltage ratings (V_CEO = −60 V / +60 V), current rating (±1 A), and power dissipation (1 W), but differ in polarity, gain profile (h_FE min/max ranges), and saturation characteristics-enabling matched push-pull design without gain skew or thermal imbalance.