onsemi BC546BTAR

Overview

BC546BTAR from ON Semiconductor is an NPN epitaxial silicon transistor designed for general-purpose switching and amplification in low-power analog and digital circuits, with V_CEO = 65 V, h_FE = 200–450 (Class B), and f_T = 300 MHz - commonly used in audio preamplifiers, signal conditioning stages, and discrete logic interface circuits.

For engineers reviewing the BC546BTAR datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain classification, saturation voltage at defined I_C/I_B, noise figure in low-level amplification, TO-92 thermal derating, and compatibility with legacy BC-series designs requiring 65 V collector-emitter breakdown.

Technical Context

The BC546BTAR operates as a single NPN bipolar junction transistor in linear or saturated mode, with base-emitter forward bias enabling controlled collector current flow up to 100 mA DC. Its epitaxial silicon construction ensures stable h_FE across temperature and reproducible V_BE(on) (580–700 mV at I_C = 2 mA).

It delivers 300 MHz current-gain bandwidth under V_CE = 5 V, I_C = 10 mA conditions, supporting RF-coupled amplifier stages up to low-VHF; Cob = 3.5–6.0 pF and Cib = 9 pF enable predictable high-frequency impedance matching in discrete gain blocks.

Key Specifications

Pinout & Package

BC546BTAR is housed in a JEDEC TO-92 3-lead molded plastic package with straight leads (Ammo packaging format), rated for 150 °C junction temperature and compatible with wave/solder-reflow profiles per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC547BTA and PN2222A, BC546BTAR uniquely combines 65 V V_CEO, Class B h_FE, and standard C-B-E TO-92 pinout - making it the only option among the three for 48 V systems requiring no layout change.

Availability

BC546BTAR is available at Aetrix Electronics and suitable for audio preamplifiers, microcontroller interface circuits, and RF signal buffering requiring stable component supply across industrial, test & measurement, and consumer electronics programs.

Supply support for BC546BTAR 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 power management, analog, sensor, and discrete solutions for automotive, industrial, and cloud infrastructure markets.

The BC546BTAR belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, originally developed by Fairchild and maintained for backward compatibility in cost-sensitive, high-volume linear and switching applications.

FAQ

What is the maximum collector-emitter voltage rating for BC546BTAR?

The BC546BTAR has a guaranteed V_CEO rating of 65 V at T_A = 25°C. This rating remains valid up to 125°C junction temperature with appropriate derating per the datasheet's thermal curves. Exceeding this voltage risks avalanche breakdown and permanent device failure. Always verify operating margin against worst-case supply transients in BC546BTAR-based designs.

Does BC546BTAR have a specified noise figure, and under what conditions?

Yes, BC546BTAR has a noise figure of 2.0–10.0 dB, measured at V_CE = 5 V, I_C = 200 μA, f = 1 kHz, and R_G = 2 kΩ. This specification applies specifically to low-level amplification scenarios such as electret microphone preamplifiers. Noise performance degrades above 10 kHz and under higher collector currents.

What is the pin configuration of BC546BTAR in the TO-92 package?

When viewing the BC546BTAR TO-92 package with the flat side facing you and leads pointing downward, the pin order from left to right is: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter (C-B-E). This matches the standard BC-series orientation and differs from PN2222A (E-B-C), so PCB layout must reflect this arrangement for correct functionality.

How does the h_FE classification of BC546BTAR affect circuit design?

BC546BTAR is classified as Class B, meaning its DC current gain is guaranteed between 200 and 450 at V_CE = 5 V and I_C = 2 mA. Designers must size base resistors to ensure minimum I_B = I_C/450 for saturation, and account for gain spread when setting bias points in linear amplifiers to avoid distortion or cutoff.

Is BC546BTAR suitable for RF amplifier applications, and what is its frequency limit?

BC546BTAR is characterized with f_T = 300 MHz at V_CE = 5 V, I_C = 10 mA, and f = 100 MHz, making it usable in VHF-band buffer and driver stages up to ~100 MHz. However, gain rolls off above f_T/10, so practical small-signal amplification is limited to ≤50 MHz with stable phase margin. It is not recommended for >200 MHz fundamental oscillation.