onsemi BC212_D74Z

Overview

BC212_D74Z from Fairchild Semiconductor is a PNP bipolar junction transistor designed for general-purpose amplification and switching at DC collector currents up to 300 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 TO-92 package - used in low-voltage audio preamplifiers, discrete logic inverters, and relay driver stages.

For engineers reviewing the BC212_D74Z datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, 50 V V_CEO rating, 300 mA I_C capability, thermal resistance (R_θJA = 200 °C/W), and suitability for linear amplification versus saturated switching in cost-sensitive discrete designs.

Technical Context

The BC212_D74Z operates as a silicon PNP BJT with fixed-emitter biasing topology, optimized for DC-coupled amplification and low-speed switching. Its h_FE range (40–60) and V_BE(on) = 0.6–0.72 V support predictable base-current-driven operation in Class-A amplifier stages and emitter-follower buffers.

Thermal design relies on its R_θJA = 200 °C/W (FR-4 PCB, 1.6″ × 1.6″ × 0.06″) and maximum T_J = 150 °C, limiting continuous power dissipation to 625 mW at 25 °C with 5.0 mW/°C derating - making it suitable for ambient-temperature-stable, non-high-frequency applications.

Key Specifications

Pinout & Package

BC212_D74Z is housed in a through-hole TO-92 package (JEDEC TO-92 variant), with leads arranged in linear configuration: Lead 1 = Collector, Lead 2 = Base, Lead 3 = Emitter (flat side facing viewer, leads down).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC212_D74Z, BC212L_D74Z offers higher minimum h_FE for lower base drive, while BC212B_D74Z enables single-transistor gain stages without cascading - both retain identical V_CEO, V_CBO, and thermal limits, ensuring direct substitution in existing TO-92 footprints without layout change.

Availability

BC212_D74Z is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic inverters, and relay driver circuits requiring stable component supply, long-term obsolescence management, and JEDEC-standard through-hole compatibility.

Supply support for BC212_D74Z 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 components before its acquisition by ON Semiconductor in 2016.

The BC212_D74Z belongs to Fairchild's legacy general-purpose BJT family, engineered for cost-effective, robust amplification and switching in industrial controls, consumer audio, and power interface circuits.

FAQ

What is the maximum continuous collector current rating for BC212_D74Z?

The BC212_D74Z has a maximum DC collector current rating of 300 mA, as specified in its Absolute Maximum Ratings table. This value assumes operation within the device's thermal limits - sustained current above ~100 mA requires attention to PCB copper area and ambient temperature to avoid exceeding the 150 °C maximum junction temperature. The BC212_D74Z must be operated below this limit to ensure reliability and prevent parametric shift.

Does BC212_D74Z have a documented f_T (transition frequency)?

No, the BC212_D74Z datasheet does not specify f_T or small-signal frequency response parameters. It is characterized for DC and low-frequency applications only, with Cob = 6 pF measured at 1 MHz. Engineers should treat BC212_D74Z as unsuitable for RF, wideband amplification, or switching above ~100 kHz. For high-frequency alternatives, consult Fairchild's RF transistor families or ON Semiconductor's newer PNP RF devices.

Can BC212_D74Z replace BC212 in existing designs?

Yes, BC212_D74Z is a valid replacement for the base BC212 part, sharing identical electrical specifications, TO-92 package, pinout, and thermal characteristics. The "_D74Z" suffix denotes Fairchild's specific tape-and-reel packaging and traceability coding - it does not indicate functional or parametric deviation. Designers may use BC212_D74Z without circuit or layout modification in all BC212-specified applications.

What is the recommended base resistor value for switching BC212_D74Z with a 3.3 V MCU GPIO?

For reliable saturation with a 3.3 V GPIO driving the base of BC212_D74Z (V_BE(sat) ≈ 1.4 V), a 1.0 kΩ resistor limits base current to ~1.9 mA, sufficient to drive 100 mA collector current at forced β = 10. This ensures deep saturation across temperature. Lower values (e.g., 680 Ω) improve margin but increase MCU output loading; verify GPIO current capability per manufacturer datasheet before final selection.

Is BC212_D74Z suitable for automotive applications?

The BC212_D74Z is not AEC-Q101 qualified and lacks automotive-grade screening, temperature range extension (–40°C to +125°C), or enhanced ESD robustness. While its rated T_J spans –55°C to +150°C, it was designed for commercial/industrial use. For automotive applications, consider ON Semiconductor's AEC-Q101 PNP transistors such as NSS20201CF or MMBT2907ALT1G - not BC212_D74Z.