onsemi BSR15

Overview

BSR15 from ON Semiconductor is a PNP epitaxial silicon transistor designed for general-purpose amplification and switching in low-voltage, medium-current applications. It features V_CEO = −40 V, I_C = −800 mA continuous, h_FE = 30–300 (depending on bias), f_T = 200 MHz, and SOT-23 package - commonly used in load switching and signal inversion circuits within consumer and industrial power management.

For engineers reviewing the BSR15 datasheet, pinout, applications, or equivalent options, key selection considerations include its PNP polarity, −500 mA switching capability at V_CE(sat) ≤ −1.6 V, thermal resistance of 357 °C/W, and compatibility with FR-4 PCB layouts requiring minimal footprint and thermal relief.

Technical Context

The BSR15 operates as a discrete bipolar junction transistor with fixed PNP polarity and epitaxial base construction, enabling stable DC gain and high-frequency response up to 200 MHz under specified bias conditions. Its breakdown ratings (V_CBO = −60 V, V_EBO = −5.0 V) support robust operation in moderate-voltage bias networks.

Designed for use in linear amplification and saturated switching modes, the BSR15 delivers verified V_CE(sat) of −0.4 V at I_C = −150 mA / I_B = −15 mA and exhibits fast switching performance: t_on = 45 ns, t_off = 100 ns, with storage time t_s = 80 ns - suitable for pulse-width modulation and digital logic interfacing.

Key Specifications

Pinout & Package

SOT-23 surface-mount package with gull-wing leads; compact 2.90 mm × 1.30 mm footprint, 1.14 mm max height, and JEDEC-standard thermal pad layout for manual or automated reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BCW68G and MMBT3906, the BSR15 offers superior current handling (−800 mA) and validated thermal performance on FR-4, making it optimal for medium-power switching where both gain stability and saturation voltage must be balanced across temperature.

Availability

BSR15 is available at Aetrix Electronics and suitable for LED driver circuits, level-shifting interfaces, DC motor control, and power supply enable switches requiring stable component supply and long-term industrial lifecycle support.

Supply support for BSR15 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, and discrete solutions for automotive, industrial, and consumer markets.

The BSR15 belongs to ON Semiconductor's legacy Fairchild PNP transistor product line, engineered for cost-sensitive, medium-current switching and amplification in space-constrained PCB environments.

FAQ

What is the maximum continuous collector current rating for the BSR15?

The BSR15 has a maximum continuous collector current rating of −800 mA at T_A = 25°C. This rating assumes proper PCB thermal relief (FR-4, 40 mm × 40 mm). Derating applies above 25°C per the 2.8 mW/°C thermal coefficient, and actual usable current depends on ambient temperature, board layout, and airflow. The BSR15 datasheet specifies this value under steady-state DC conditions, not pulsed operation.

Does the BSR15 support high-frequency switching applications?

Yes, the BSR15 supports high-frequency switching with a current gain bandwidth product (f_T) of 200 MHz at I_C = −50 mA and V_CE = −20 V. Measured switching times - t_on = 45 ns, t_off = 100 ns - confirm suitability for PWM-driven loads up to ~20 kHz. However, full 200 MHz operation requires careful impedance matching and low-inductance layout; the BSR15 is not intended for RF power amplification.

What is the pin configuration of the BSR15 in the SOT-23 package?

The BSR15 uses standard SOT-23 pinout: Pin 1 is Base, Pin 2 is Emitter, and Pin 3 is Collector. This matches JEDEC TO-236AB and is consistent across ON Semiconductor's PNP SOT-23 transistors. The device marking "T7" appears adjacent to Pin 1. Always verify orientation using the datasheet mechanical drawing - incorrect placement causes functional failure due to reversed polarity.

Can the BSR15 replace the MMBT3906 in existing designs?

The BSR15 can replace the MMBT3906 only if the design requires higher current capability (−800 mA vs. −200 mA) and can accommodate its broader h_FE range (30–300 vs. 100–300). Because both share SOT-23 packaging and identical pinout, no PCB changes are needed. However, the BSR15's higher power dissipation and different small-signal capacitance (C_cb = 8.0 pF vs. 4.0 pF) may affect high-frequency stability - verify loop compensation in amplifier applications.

What thermal management guidance applies to the BSR15 in SOT-23?

The BSR15 has a junction-to-ambient thermal resistance (R_θJA) of 357 °C/W when mounted on a standard FR-4 PCB (40 mm × 40 mm × 1.5 mm). To maintain T_J ≤ 150°C, keep power dissipation below 350 mW at 25°C ambient. Use copper pour under the collector pad and thermal vias for sustained >200 mA operation. The BSR15 datasheet explicitly defines this R_θJA value under those exact board conditions - alternate layouts require empirical thermal validation.