onsemi BC307B

Overview

BC307B from ON Semiconductor is a PNP silicon small-signal amplifier transistor in TO-92 package, rated for −45 V_CEO, −100 mA_C, 350 mW at T_A = 25°C, with h_FE = 120–290 (I_C = −10 mA, V_CE = −5 V), and f_T = 280 MHz - used in low-noise audio preamplifier stages and discrete bias networks.

For engineers reviewing the BC307B datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP gain bandwidth trade-offs, thermal derating behavior at elevated ambient temperatures, junction-to-case thermal resistance (125 °C/W), and Pb-free TO-92 mechanical compatibility with legacy through-hole assembly lines.

Technical Context

The BC307B operates as a linear PNP bipolar junction transistor optimized for analog amplification and switching below 300 MHz. Its DC current gain exhibits strong collector-current dependency (h_FE peaks near −10 mA and declines above −50 mA), and its noise figure is specified at 2.0 dB typical (I_C = −0.2 mA, R_S = 2 kΩ, f = 1 kHz).

Thermal design requires attention to both ambient- and case-referenced dissipation limits: 350 mW at T_A = 25°C with 2.8 mW/°C derating, or 1.0 W at T_C = 25°C with 8.0 mW/°C derating. The device's V_BE(on) is −0.62 V typical at I_C = −2 mA, supporting predictable base drive in emitter-follower configurations.

Key Specifications

Pinout & Package

BC307B is housed in a standard TO-92 (Case 29, Style 17) plastic package with axial leads, compatible with manual soldering and wave soldering processes. Lead finish is Pb-free per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC307B, BC327-40 offers higher current handling and gain but looser thermal gain tracking, while 2N3906 trades bandwidth and voltage margin for broader distributor availability and lower unit cost in non-VHF designs.

Availability

BC307B is available at Aetrix Electronics and suitable for audio preamplifiers, discrete bias networks, signal inverters, and LED driver switches requiring stable component supply and RoHS-compliant through-hole assembly.

Supply support for BC307B 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 (now onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and consumer markets.

The BC307B belongs to the BC307 family of general-purpose PNP transistors designed for low-noise amplification and reliable switching in cost-sensitive, space-constrained analog circuits.

FAQ

What is the maximum operating temperature for BC307B?

The BC307B has an operating junction temperature range of −55°C to +150°C. Its thermal resistance from junction to case is 125°C/W, meaning that with proper heatsinking, it can sustain continuous operation at elevated ambient temperatures when power dissipation remains within the derated limits - for example, at 75°C ambient, maximum allowable power drops to approximately 245 mW under free-air conditions.

Is BC307B pin-compatible with BC307C?

Yes, BC307B and BC307C share identical TO-92 packaging, pinout (Collector-Base-Emitter on pins 1-2-3), and absolute maximum ratings. The only difference is DC current gain: BC307B is binned 120–290, while BC307C is binned 180–460 at I_C = −10 mA. Substitution is electrically valid if gain tolerance requirements permit the wider spread.

Does BC307B support Pb-free soldering processes?

Yes, the BC307BZL1G variant (explicitly referenced in the ordering row) is Pb-free and qualified per J-STD-020. It withstands peak reflow temperatures up to 260°C for 10 seconds and meets IPC/JEDEC standards for moisture sensitivity level 1, eliminating bake requirements prior to assembly.

What is the typical V_BE(on) of BC307B at I_C = −2 mA?

The BC307B exhibits a typical base-emitter on voltage of −0.62 V at I_C = −2 mA and V_CE = −5 V. This value is critical for designing accurate bias networks and calculating base resistor values in common-emitter amplifier configurations where predictable DC operating points are required.

Can BC307B be used in RF oscillator circuits?

Yes, the BC307B's 280 MHz current-gain bandwidth product (f_T) and low output admittance support use in VHF-range LC oscillators and Colpitts configurations up to ~100 MHz. Its noise figure of 2.0 dB also contributes to phase noise performance in local oscillator stages where signal purity is essential.