onsemi BSR17A

Overview

BSR17A from ON Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for amplification and switching in low-power analog and digital circuits. It delivers DC current gain (hFE) of 40–300 across 0.1–100 mA collector current, supports 40 V VCEO and 60 V VCBO, and operates up to 300 MHz transition frequency (fT), making it suitable for signal conditioning in consumer audio preamps and logic-level interface drivers.

For engineers reviewing the BSR17A datasheet, pinout, applications, or equivalent options, key selection considerations include its SOT-23 package footprint, 200 mA maximum DC collector current, 350 mW power dissipation at 25°C, and verified performance in linear amplification (hie = 1.0–10 kΩ) and fast switching (tr = 4 ns, tf = 50 ns).

Technical Context

The BSR17A employs a silicon planar epitaxial process (Process 23) optimized for balanced gain-bandwidth and low saturation voltage. Its fT of 300 MHz at IC = 20 mA, VCE = 20 V confirms suitability for RF amplifier stages up to VHF, while VCE(sat) ≤ 0.3 V at IC = 50 mA / IB = 5 mA enables efficient low-side switching in 3.3 V/5 V logic-controlled loads.

Thermal design is constrained by RθJA = 357°C/W on FR-4 PCB (40 mm × 40 mm × 1.5 mm), requiring derating above 25°C at 2.8 mW/°C. Junction temperature range (−55°C to +150°C) and storage rating match industrial-grade operation, with Ccb = 4.0 pF and Ceb = 8.0 pF supporting stable high-frequency bias networks.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with standard lead configuration: emitter (E), base (B), collector (C) arranged in linear order (pin 1 = E, pin 2 = B, pin 3 = C), marked "U92" on top surface.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose amplifier applications.

Compared with MMBT3904LT1G and BC847BW, the BSR17A offers superior high-frequency response (300 MHz fT) and broader hFE range (40–300), making it optimal for VHF-capable amplifiers and fast-switching interfaces where gain consistency across current levels is critical.

Availability

BSR17A is available at Aetrix Electronics and suitable for audio preamplifiers, microcontroller interface drivers, and industrial sensor signal conditioning requiring stable component supply and long-term industrial lifecycle support.

Supply support for BSR17A 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 (formerly Fairchild Semiconductor) is a global semiconductor manufacturer specializing in power management, analog, and discrete devices for automotive, industrial, and consumer markets.

The BSR17A belongs to ON Semiconductor's general-purpose bipolar transistor product line, engineered for cost-effective, reliable amplification and switching in non-critical signal-path applications across industrial and consumer electronics.

FAQ

What is the maximum continuous collector current rating for the BSR17A?

The BSR17A has a maximum DC collector current (IC) rating of 200 mA at Ta = 25°C, as specified in its Absolute Maximum Ratings table. This rating assumes proper PCB thermal relief (FR-4, 40 mm × 40 mm × 1.5 mm); actual usable current must be reduced per the 2.8 mW/°C derating curve above 25°C ambient to maintain junction temperature ≤150°C. The BSR17A remains functional up to 100 mA in switching applications per its datasheet-defined useful dynamic range.

Does the BSR17A have a SPICE model available for circuit simulation?

Yes, the BSR17A includes a published PSpice-compatible behavioral model with parameters including Is = 6.734 fA, Bf = 416.4, Cjc = 3.638 pF, and Tf = 301.2 ps. This model is documented in the official BSR17A Rev. A datasheet and supports accurate AC, transient, and DC operating point analysis in amplifier and switching circuit designs using the BSR17A.

What is the pin configuration of the BSR17A in its SOT-23 package?

The BSR17A uses standard SOT-23 pinout: Pin 1 = Emitter (E), Pin 2 = Base (B), Pin 3 = Collector (C), with top-side marking "U92". This matches JEDEC MO-178 mechanical outline and is electrically identical to industry-standard NPN SOT-23 layouts, enabling drop-in replacement in existing footprints designed for compatible transistors like MMBT3904.

Can the BSR17A be used in RF amplifier applications?

Yes, the BSR17A is qualified for RF amplifier use up to 100 MHz due to its 300 MHz transition frequency (fT) measured at IC = 20 mA and VCE = 20 V. Its Ccb = 4.0 pF and Ceb = 8.0 pF support stable matching networks, and its hfe = 100–400 at 1 kHz ensures sufficient gain margin in tuned amplifier stages using the BSR17A.

What is the guaranteed minimum DC current gain (hFE) of the BSR17A at 10 mA collector current?

The BSR17A guarantees hFE ≥ 100 at IC = 10 mA and VCE = 1.0 V, per its Electrical Characteristics table. The device also specifies hFE ≥ 40 at IC = 0.1 mA and ≥ 30 at IC = 100 mA, confirming usable gain across three decades of collector current - a key differentiator for wide-dynamic-range amplifier and switch designs using the BSR17A.