onsemi BC557BTFR

Overview

BC557BTFR from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and linear amplification in low-power analog and digital circuits. It features V_CEO = −45 V, I_C = −100 mA, h_FE = 110–800 (Class B), f_T = 150 MHz, and V_BE(on) = −600 to −750 mV at I_C = −2 mA - enabling reliable operation in bias networks, signal inversion stages, and discrete logic interfaces.

For engineers reviewing the BC557BTFR datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92-3 (case 135AR) package, complementary pairing with BC547 series NPN devices, low-noise capability (NF = 2–10 dB), and RoHS-compliant Pb-free/halogen-free construction suitable for industrial and consumer-grade designs.

Technical Context

This PNP bipolar junction transistor operates with reverse-polarity biasing: collector and emitter terminals require negative voltage relative to base for active conduction. Its h_FE classification (B) guarantees DC current gain between 200 and 450 at V_CE = −5 V and I_C = −2 mA, supporting stable small-signal amplification across temperature ranges from −55°C to +150°C.

The device exhibits V_CE(sat) ≤ −300 mV at I_C = −10 mA / I_B = −0.5 mA and ≤ −650 mV at I_C = −100 mA / I_B = −5 mA, confirming robust saturation performance for switching applications. Cob = 6 pF at V_CB = −10 V ensures minimal high-frequency coupling in audio and RF-adjacent stages.

Key Specifications

Pinout & Package

BC557BTFR is housed in a TO-92-3 plastic package (case 135AR), lead-formed configuration, with standard through-hole mounting and 4.83 mm × 4.76 mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC557BTFR, BC557BTA offers identical performance in non-automated settings, while BC558BTA trades voltage headroom for marginal cost reduction - making BC557BTFR the optimal choice for automated production and designs requiring ≥40 V reverse-blocking capability.

Availability

BC557BTFR is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic inverters, LED driver circuits, and current mirror references requiring stable component supply, consistent parametric performance, and RoHS-compliant manufacturing.

Supply support for BC557BTFR 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC557BTFR belongs to onsemi's legacy BC5xx PNP/NPN transistor family, engineered for cost-sensitive, high-reliability discrete analog and switching functions in general-purpose electronics - emphasizing manufacturability, thermal stability, and long-term supply assurance.

FAQ

What is the package type and lead configuration of BC557BTFR?

The BC557BTFR uses a TO-92-3 plastic package (case 135AR) with lead-formed (bent) configuration optimized for tape-and-reel automated placement. Its dimensions are 4.83 mm × 4.76 mm, and pin 1 is collector, pin 2 is base, pin 3 is emitter - matching standard BC5xx orientation. This configuration ensures compatibility with industry-standard pick-and-place equipment and manual soldering workflows.

Is BC557BTFR RoHS compliant and lead-free?

Yes, BC557BTFR is fully RoHS compliant and manufactured as Pb-free, halogen-free, and BFR-free per EU Directive 2011/65/EU. The device meets onsemi's green material specifications and carries no exemptions - making it suitable for environmentally regulated end products including consumer electronics, industrial controls, and medical devices outside life-support classification.

What is the maximum collector-emitter voltage rating for BC557BTFR?

The BC557BTFR has a maximum collector-emitter voltage (V_CEO) rating of −45 V at T_A = 25°C. This rating applies under DC conditions and defines the absolute upper limit for reverse-biased voltage across the collector and emitter terminals. Exceeding this value risks avalanche breakdown and permanent device degradation.

How does BC557BTFR compare to BC556B in terms of voltage rating and use cases?

BC557BTFR has V_CEO = −45 V and V_CBO = −50 V, whereas BC556B offers higher ratings of −65 V and −80 V respectively. This makes BC556B preferable in 60 V systems like automotive subsystems or industrial power supplies, while BC557BTFR is optimized for 45 V max applications such as 24 V industrial I/O, 36 V telecom interfaces, and general-purpose 5–12 V logic-level circuits.

Can BC557BTFR be used as a direct replacement for BC557BTA in automated assembly?

Yes, BC557BTFR is functionally identical to BC557BTA - same die, same electrical characteristics, same TO-92-3 case 135AR package - with the sole difference being tape-and-reel packaging (BTFR) versus fan-fold (BTA). BC557BTFR is specifically intended for SMT automation, offering precise part orientation and consistent feeding for high-speed placement systems without rework.