onsemi BC212LB

Overview

BC212LB from Fairchild Semiconductor is a PNP general-purpose bipolar junction transistor (BJT) designed for low-power amplification and switching at collector currents up to 100 mA. It features V_CEO = 50 V, V_CBO = 60 V, h_FE = 40–60 (at I_C = 2 mA), V_CE(sat) = 0.6 V (I_C = 100 mA, I_B = 5 mA), and operates across –55°C to +150°C junction temperature range - commonly used in audio preamplifier stages and discrete logic interface circuits.

For engineers reviewing the BC212LB datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92 package, PNP polarity, DC current gain tolerance, saturation voltage under load, and thermal resistance (R_θJA = 357°C/W), all critical for bias stability and power dissipation in compact analog signal paths.

Technical Context

The BC212LB is a silicon planar epitaxial PNP transistor optimized for linear amplification and low-speed switching. Its h_FE is specified at two operating points (I_C = 10 µA and 2 mA), supporting both micro-power biasing and moderate-current drive. The device exhibits low noise figure (NF = 10 dB at 1 kHz, R_G = 2 kΩ), making it suitable for low-level signal amplification where noise contribution must be minimized.

Thermal design is constrained by its TO-92 package: R_θJC = 125°C/W and maximum power dissipation of 350 mW at 25°C, derating linearly at 2.8 mW/°C above ambient. Output capacitance (C_ob = 6 pF at V_CE = 10 V, f = 1 MHz) supports stable operation in audio-frequency small-signal applications without unintended resonance.

Key Specifications

Pinout & Package

BC212LB is housed in a standard through-hole TO-92 package with 3 leads. Lead identification (viewed from flat side, tab down): Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC212L and BC557B, the BC212LB offers the narrowest h_FE spread (40–60) and highest V_CEO among TO-92 PNP amplifiers in its class, making it optimal for designs prioritizing voltage margin and predictable bias stability over maximum gain.

Availability

BC212LB is available at Aetrix Electronics and suitable for audio preamplifier stages, discrete logic level shifters, and temperature-stable bias generators requiring stable component supply and long-term obsolescence management.

Supply support for BC212LB 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.

The BC212LB belongs to Fairchild's legacy general-purpose BJT family, engineered for cost-sensitive, medium-frequency analog signal conditioning and switching in consumer, industrial, and instrumentation equipment.

FAQ

What is the pin configuration of the BC212LB?

The BC212LB uses a TO-92 package with lead identification viewed from the flat side (tab down): Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base. This E-C-B order is standard for Fairchild's PNP transistors in this series and matches mechanical drawings in Rev. A1 (August 2002) datasheet. Confirm orientation using the datasheet's package dimension diagram before PCB layout.

What is the maximum collector current rating for BC212LB?

The BC212LB has a continuous collector current rating of 100 mA, as specified in its Absolute Maximum Ratings table. This value assumes proper thermal management - at ambient temperatures above 25°C, power dissipation must be derated by 2.8 mW/°C. Exceeding 100 mA continuously risks exceeding the 150°C maximum junction temperature and permanent device degradation.

Does BC212LB support audio-frequency amplification?

Yes, the BC212LB supports audio-frequency amplification with verified performance: small-signal current gain (h_FE) is characterized at 1 kHz, output capacitance (C_ob = 6 pF) limits high-frequency roll-off, and noise figure (NF = 10 dB) ensures low added noise in preamplifier stages. Its V_CE(sat) and h_FE stability across bias points further enable clean, distortion-free gain in common-emitter configurations up to 20 kHz.

What is the thermal resistance of BC212LB, and how does it affect PCB layout?

The BC212LB has a junction-to-ambient thermal resistance (R_θJA) of 357°C/W in free-air conditions. This high value means even modest power dissipation (e.g., 100 mW) causes ~36°C junction rise above ambient - requiring careful PCB layout: use generous copper pour on collector pad, avoid enclosing the TO-92 in tight enclosures, and consider derating power at elevated ambient temperatures per the 2.8 mW/°C derating curve.

Is BC212LB suitable for use in life support systems?

No, BC212LB is not authorized for use in life support devices or systems. Per Fairchild's Life Support Policy (Rev. A1, August 2002), its use in applications where failure could result in significant injury - such as surgical implants, life-sustaining equipment, or safety-critical monitoring - requires express written approval from ON Semiconductor (successor to Fairchild). Designers must select components explicitly qualified for such roles.