onsemi BC548BTF

Overview

BC548BTF from ON Semiconductor is an NPN epitaxial silicon transistor optimized for general-purpose switching and low-noise amplification, with V_CEO = 30 V, h_FE = 200–450 (Class B), and f_T = 300 MHz. It operates reliably in audio preamplifiers, digital logic interfaces, and sensor signal conditioning circuits at ambient temperatures up to +150°C.

For engineers reviewing the BC548BTF datasheet, pinout, applications, or equivalent options, this page delivers verified package mapping (TO-92), validated DC gain range, saturation voltage behavior under 10 mA/0.5 mA drive, noise figure (2.0–10.0 dB), and direct alternatives aligned to Fairchild/ON Semi's BC54x family nomenclature and electrical grouping.

Technical Context

This device belongs to the legacy BC546–BC550 NPN transistor family originally introduced by Fairchild and now maintained by ON Semiconductor. Its epitaxial base construction enables stable h_FE across temperature and consistent V_BE(on) (580–700 mV at I_C = 2 mA) for predictable biasing in discrete amplifier stages.

Designed for through-hole assembly in cost-sensitive consumer and industrial electronics, BC548BTF uses a JEDEC TO-92 3-lead straight-lead configuration with Collector (Pin 1), Base (Pin 2), Emitter (Pin 3). It is not rated for low-noise operation like BC549/BC550, nor high-voltage use like BC546 (V_CEO = 65 V).

Key Specifications

Pinout & Package

BC548BTF is housed in a JEDEC-standard TO-92 plastic package with straight leads (bulk/ammo/tape-and-reel variants), measuring 4.6 mm × 3.3 mm × 4.0 mm. Pin identification follows standard orientation: flat side facing viewer, leads down, left-to-right = Pin 1 (Collector), Pin 2 (Base), Pin 3 (Emitter).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC547BTF and BC548CTA, BC548BTF offers the optimal balance of voltage rating, gain consistency, and saturation performance for cost-sensitive 5–12 V switching and mid-gain amplification-without over-spec'ing voltage or gain where unnecessary.

Availability

BC548BTF is available at Aetrix Electronics and suitable for audio preamplifiers, digital level shifters, and relay driver circuits requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.

Supply support for BC548BTF 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 supplier of energy-efficient semiconductor components, specializing in power management, analog, and discrete devices for automotive, industrial, and consumer markets.

BC548BTF belongs to the BC54x family of general-purpose NPN transistors, designed for broad adoption in cost-driven, reliability-critical linear and switching applications where proven performance and long-lifecycle support are essential.

FAQ

What is the maximum collector-emitter voltage rating for BC548BTF?

The BC548BTF has a maximum collector-emitter voltage (V_CEO) rating of 30 V. This value is specified in the Absolute Maximum Ratings table of the official ON Semiconductor datasheet for the BC546–BC550 family. Exceeding this voltage risks permanent breakdown of the BC548BTF junction, especially under high-temperature or transient conditions. Designers must ensure that BC548BTF operates within this limit in all circuit configurations, including flyback spikes in inductive loads.

Does BC548BTF have a guaranteed DC current gain range?

Yes, BC548BTF is binned as Class B with a guaranteed h_FE range of 200 to 450 at V_CE = 5 V and I_C = 2 mA. This specification is explicitly defined in the "hFE Classification" table of the BC546–BC550 datasheet. The BC548BTF gain range enables predictable biasing in amplifier and switching circuits without requiring individual unit testing, supporting high-yield manufacturing of BC548BTF-based designs.

What package type and pin configuration does BC548BTF use?

BC548BTF uses a JEDEC TO-92 plastic package with straight leads and a standard 3-pin configuration: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter. This mechanical form factor is confirmed in Figures 7 and 8 of the BC546–BC550 datasheet and matches industry-standard TO-92 footprints. The BC548BTF pinout is identical across all members of the BC54x family, enabling direct PCB footprint reuse.

Is BC548BTF suitable for low-noise audio amplification?

BC548BTF has a noise figure of 2.0–10.0 dB at V_CE = 5 V, I_C = 200 μA, and f = 1 kHz, making it usable in non-critical audio preamp stages-but it is not optimized for ultra-low-noise applications. For such cases, BC549BTF or BC550CBU (NF = 1.2–4.0 dB) are preferred. The BC548BTF noise performance is adequate for line-level buffering or microphone amplification where signal-to-noise ratio requirements are moderate.

How does BC548BTF differ from BC547BTF in practical circuit design?

BC548BTF and BC547BTF share identical h_FE Class B binning and TO-92 packaging, but BC547BTF has a higher V_CEO rating of 45 V versus 30 V for BC548BTF. In practice, this means BC547BTF tolerates larger voltage transients and is safer in 24 V systems, while BC548BTF is sufficient-and often preferred-for 5–12 V logic and signal paths where lower voltage rating correlates with tighter parameter control and cost efficiency. Both remain functionally interchangeable only if the BC548BTF's 30 V ceiling is respected.