onsemi BC557B_D11Z

Overview

BC557B_D11Z 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, h_FE = 200–450 (Class B), I_C = −100 mA DC, V_BE(on) ≈ −660 mV at I_C = −2 mA, and f_T = 150 MHz - enabling use in audio preamplifiers, level shifters, and discrete logic interfaces.

For engineers reviewing the BC557B_D11Z datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, TO-92-3 package compatibility, Class B h_FE range, −45 V V_CEO rating, and RoHS-compliant Pb-free construction per onsemi Rev. 3 (June 2024).

Technical Context

This device operates as a medium-voltage, medium-current PNP bipolar junction transistor with complementary pairing to the BC547 series. Its −45 V V_CEO and −50 V V_CBO support operation in negative-rail biasing schemes, while its 150 MHz f_T enables stable gain up to mid-audio frequencies.

The BC557B_D11Z exhibits low-noise performance (NF = 2–10 dB at 1 kHz) and defined saturation behavior: V_CE(sat) ≤ −300 mV at I_C = −10 mA/I_B = −0.5 mA, and V_BE(sat) ≤ −700 mV under same conditions - critical for predictable switching thresholds in discrete gate drivers and current mirrors.

Key Specifications

Pinout & Package

BC557B_D11Z is housed in a TO-92-3 plastic package (Case 135AR), with standardized leadform orientation: flat side facing viewer, leads downward, left-to-right pin order as Collector–Base–Emitter.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC557B_D11Z, BC557BTA offers identical performance in a different packaging format ideal for benchtop use, while BC558BTA trades 15 V of collector-emitter voltage margin for potential cost reduction - making BC557B_D11Z the optimal choice for −45 V–capable designs requiring reliability across voltage transients.

Availability

BC557B_D11Z is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic level shifters, and LED driver switches requiring stable component supply, consistent h_FE binning, and RoHS-compliant manufacturing.

Supply support for BC557B_D11Z 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 IoT markets.

The BC557 series belongs to onsemi's legacy general-purpose bipolar transistor family, engineered for cost-sensitive, high-reliability discrete signal conditioning and switching in consumer, industrial, and communication equipment.

FAQ

What is the maximum collector-emitter voltage rating for BC557B_D11Z?

The BC557B_D11Z has a maximum collector-emitter voltage (V_CEO) rating of −45 V, as specified in the Absolute Maximum Ratings table of the official onsemi datasheet (Rev. 3, June 2024). This rating applies under standard test conditions (T_A = 25°C) and defines the upper limit of reverse bias the transistor can withstand in common-emitter configuration without breakdown. Exceeding this value risks permanent damage.

Is BC557B_D11Z RoHS compliant and lead-free?

Yes, BC557B_D11Z is fully RoHS compliant and lead-free, as confirmed in the Features section of the onsemi datasheet. It meets EU Directive 2011/65/EU requirements and is also halogen-free and BFR-free. The device uses Pb-free terminations and complies with JEDEC J-STD-020 moisture sensitivity level (MSL) standards appropriate for its TO-92-3 package.

What is the h_FE range for BC557B_D11Z and how is it binned?

The BC557B_D11Z is binned to h_FE Class B, with a guaranteed DC current gain range of 200 to 450 at V_CE = −5 V and I_C = −2 mA. This classification is explicitly defined in the h_FE Classification table of the onsemi datasheet and distinguishes it from Class A (110–220) and Class C (420–800) variants within the same BC557 family.

Can BC557B_D11Z be used as a direct replacement for BC557BTA?

Yes, BC557B_D11Z is functionally and electrically identical to BC557BTA - sharing identical V_CEO, h_FE Class B, f_T, package (TO-92-3 Case 135AR), and RoHS compliance. The "D11Z" suffix denotes a tape-and-reel packaging variant per onsemi's ordering nomenclature, whereas "BTA" indicates Fan-Fold packaging. No circuit or layout changes are needed for substitution.

What is the typical noise figure of BC557B_D11Z and under what conditions is it measured?

The BC557B_D11Z has a noise figure (NF) of 2–10 dB, measured at 1 kHz with V_CE = −5 V, I_C = −200 µA, and source resistance R_G = 2 kΩ. This specification is documented in the Electrical Characteristics table for the BC556/BC557/BC558 group and confirms suitability for low-noise small-signal amplification tasks such as microphone preamplifiers and sensor interface stages.