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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi BC557B_J35Z

Name: BC557B_J35Z
Brand: onsemi
SKU: BC557B_J35Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC557B_J35Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: BC557B_J35Z.pdf

Description:: TRANS PNP 45V 0.1A TO-92-3

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Product details

Overview

BC557B_J35Z from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and 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_J35Z datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92-3 package compatibility, −45 V collector-emitter breakdown rating, Class B h_FE range, low-noise capability (NF = 2–10 dB), and complementarity to BC547 series NPN transistors.

Technical Context

The BC557B_J35Z operates as a medium-gain, medium-voltage PNP bipolar junction transistor with fixed-emitter biasing topology. Its h_FE classification (B: 200–450) ensures predictable current amplification in linear amplifier stages, while V_CEO = −45 V and V_CBO = −50 V support operation in negative-rail signal conditioning and high-side switch configurations up to −45 V.

Thermal performance is defined by R_JA = 250 °C/W (FR-4 PCB, 76 mm × 114 mm), PD = 500 mW at 25°C with 4.0 mW/°C derating. Noise figure (2–10 dB at 1 kHz) and f_T = 150 MHz confirm suitability for audio-frequency amplification and moderate-speed switching below 30 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V - Maximum safe collector-emitter reverse voltage before breakdown in common-emitter configuration.
h_FE (Class B)	200–450 - Predictable DC current gain range at V_CE = −5 V, I_C = −2 mA; enables stable biasing in amplifier designs.
I_C (DC)	−100 mA - Continuous collector current limit; supports load switching up to ~100 mA with adequate heatsinking.
f_T	150 MHz - Unity-gain bandwidth at V_CE = −5 V, I_C = −10 mA; suitable for audio and low-MHz signal amplification.
NF	2–10 dB - Noise figure at 1 kHz, V_CE = −5 V, I_C = −200 µA, R_G = 2 kΩ; confirms low-noise performance in preamp stages.
V_BE(on)	−600 to −750 mV - Base-emitter turn-on voltage range; critical for accurate bias network design in linear applications.
C_ob	6 pF - Output capacitance at V_CB = −10 V; impacts high-frequency stability and bandwidth in RF-adjacent circuits.

Pinout & Package

BC557B_J35Z is housed in a TO-92-3 plastic package (Case 135AR), with standard leadform orientation: flat side facing viewer, leads down, left-to-right pin order = Collector (1), Base (2), Emitter (3).

Pin/Terminal	Circuit Role	Design Meaning
1 (Left)	Collector	Primary current sink terminal; connects to most negative supply rail or load return path in PNP configurations.
2 (Center)	Base	Control input; requires current-limited negative drive relative to emitter to enable conduction.
3 (Right)	Emitter	Current source terminal; typically tied to higher-potential node (e.g., V_CC) in common-emitter or common-base topologies.

Key Features

Feature	Design Value
Complementary Pairing	Designed as direct PNP counterpart to BC547 series NPN transistors, enabling matched push-pull and differential pair implementations.
Low-Noise Amplification	Specified NF = 2–10 dB at 1 kHz supports high-fidelity audio preamplifier stages without added noise degradation.
High-Voltage Tolerance	V_CEO = −45 V allows operation in industrial control rails, automotive sensor interfaces, and legacy ±15 V systems.
Pb-Free & RoHS Compliance	Meets EU RoHS Directive 2011/65/EU and halogen-free/BFR-free requirements for environmentally compliant manufacturing.
TO-92 Mechanical Standardization	Case 135AR footprint ensures drop-in compatibility with existing through-hole PCB layouts using industry-standard TO-92 tooling and assembly processes.

Applications

Audio Preamp Stage	Discrete Logic Level Shifter
Use Scenario: Low-noise voltage amplification of microphone or line-level signals in battery-powered portable audio devices. IC Role / Device Role / Timing Role: PNP small-signal amplifier in common-emitter configuration with emitter degeneration for gain stability. Use Value: 2–10 dB noise figure and 150 MHz f_T preserve signal integrity across 20 Hz–20 kHz bandwidth without requiring op-amps.	Use Scenario: Translating TTL/CMOS logic levels between +5 V and −5 V domains in mixed-supply interface circuits. IC Role / Device Role / Timing Role: Active pull-up switch controlled by NPN driver, providing fast, low-offset level inversion. Use Value: V_CE(sat) ≤ −300 mV at I_C = −10 mA ensures minimal voltage drop and clean logic thresholds.
Industrial Sensor Interface	LED Driver Switch
Use Scenario: Conditioning output from thermistor or RTD bridges in programmable logic controller (PLC) analog input modules. IC Role / Device Role / Timing Role: High-input-impedance emitter follower buffer isolating bridge from ADC input. Use Value: h_FE ≥ 200 ensures sufficient current drive into 10 kΩ ADC sample-and-hold networks without loading error.	Use Scenario: Driving indicator LEDs from microcontroller GPIO pins with active-high logic polarity. IC Role / Device Role / Timing Role: High-side switch controlling LED anode connection to positive rail. Use Value: I_C = −100 mA rating supports driving multiple parallel LEDs (e.g., 3× 20 mA) with margin.

Audio Preamp Stage

Discrete Logic Level Shifter

Use Scenario: Low-noise voltage amplification of microphone or line-level signals in battery-powered portable audio devices.

IC Role / Device Role / Timing Role: PNP small-signal amplifier in common-emitter configuration with emitter degeneration for gain stability.

Use Value: 2–10 dB noise figure and 150 MHz f_T preserve signal integrity across 20 Hz–20 kHz bandwidth without requiring op-amps.

Use Scenario: Translating TTL/CMOS logic levels between +5 V and −5 V domains in mixed-supply interface circuits.

IC Role / Device Role / Timing Role: Active pull-up switch controlled by NPN driver, providing fast, low-offset level inversion.

Use Value: V_CE(sat) ≤ −300 mV at I_C = −10 mA ensures minimal voltage drop and clean logic thresholds.

Industrial Sensor Interface

LED Driver Switch

Use Scenario: Conditioning output from thermistor or RTD bridges in programmable logic controller (PLC) analog input modules.

IC Role / Device Role / Timing Role: High-input-impedance emitter follower buffer isolating bridge from ADC input.

Use Value: h_FE ≥ 200 ensures sufficient current drive into 10 kΩ ADC sample-and-hold networks without loading error.

Use Scenario: Driving indicator LEDs from microcontroller GPIO pins with active-high logic polarity.

IC Role / Device Role / Timing Role: High-side switch controlling LED anode connection to positive rail.

Use Value: I_C = −100 mA rating supports driving multiple parallel LEDs (e.g., 3× 20 mA) with margin.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC557C_J35Z	Higher h_FE range (420–800); otherwise identical ratings and package.	Better suited for high-gain amplifier stages where precise bias stability is less critical than maximum signal swing.	Select BC557C_J35Z when gain > 400 is required and temperature drift of h_FE is acceptable.
MMBT557LT1G	SOT-23 package (smaller footprint), same V_CEO/I_C, h_FE = 125–400 (unclassified), slightly higher V_BE(on).	Preferred for space-constrained PCBs; not pin-compatible due to SOT-23 vs. TO-92 pinout and thermal mass.	Choose MMBT557LT1G only when board area is constrained and re-layout for SOT-23 is feasible.

Compared with BC557C_J35Z and MMBT557LT1G, BC557B_J35Z offers optimal balance of gain predictability (200–450), proven thermal reliability in TO-92, and broad design heritage - making it ideal for cost-sensitive, through-hole production where consistent mid-range h_FE simplifies bias design.

Availability

BC557B_J35Z is available at Aetrix Electronics and suitable for audio preamplifiers, industrial sensor interfaces, and discrete logic level shifters requiring stable component supply, long-term manufacturability, and RoHS-compliant through-hole assembly.

Supply support for BC557B_J35Z 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC557 series belongs to onsemi's legacy general-purpose bipolar transistor product line, engineered for reliability, consistency, and ease of use in analog signal conditioning, switching, and complementary circuit design across consumer and industrial markets.

FAQ

What is the maximum collector-emitter voltage rating for BC557B_J35Z?

The BC557B_J35Z has a maximum collector-emitter voltage (V_CEO) rating of −45 V under DC conditions at T_A = 25°C. This rating applies to common-emitter configuration with base open. Exceeding this voltage risks avalanche breakdown and permanent device damage. Derating is not specified beyond ambient temperature effects on power dissipation.

Is BC557B_J35Z pin-compatible with BC547 series NPN transistors?

Yes - BC557B_J35Z shares identical TO-92-3 (Case 135AR) mechanical dimensions and pinout (C-B-E) with BC547 series NPN transistors, enabling direct physical placement in complementary circuits. However, electrical polarity is inverted: BC557B_J35Z sinks current at the collector, while BC547 sources it. Layout reuse is possible, but schematic polarity must be reversed.

What h_FE range does BC557B_J35Z guarantee?

BC557B_J35Z is classified as Class B, guaranteeing a DC current gain (h_FE) range of 200 to 450 when measured at V_CE = −5 V and I_C = −2 mA. This range is verified per onsemi's production test flow and appears in the official datasheet's h_FE Classification table - distinct from Class A (110–220) and Class C (420–800) variants.

Can BC557B_J35Z be used in high-frequency amplifier designs?

BC557B_J35Z has a current gain bandwidth product (f_T) of 150 MHz, making it suitable for amplification up to approximately 10–15 MHz with usable gain. It is not recommended for RF power amplification or GHz-range signal paths. For audio and low-MHz instrumentation, its 6 pF output capacitance and low noise figure ensure stable, high-fidelity performance in BC557B_J35Z-based designs.

Does BC557B_J35Z meet RoHS and halogen-free requirements?

Yes - BC557B_J35Z is explicitly stated in the onsemi datasheet as Pb-free, halogen-free/BFR-free, and RoHS compliant (Directive 2011/65/EU). This compliance is confirmed in the "Features" section and reinforced in the ordering information, where all listed variants (including BC557BTA) specify Pb-free packaging in Case 135AR.

BC557B_J35Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 650mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 15nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 150MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC557B_J35Z FAQ

1.How can I place an order for BC557B_J35Z through Aetrix?

Please submit a Request for Quotation (RFQ) for BC557B_J35Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BC557B_J35Z reliable?

The price and inventory of BC557B_J35Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC557B_J35Z is usually 5 days.

3.What payment methods are accepted for BC557B_J35Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC557B_J35Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC557B_J35Z?

BC557B_J35Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC557B_J35Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BC557B_J35Z?

For technical support, including BC557B_J35Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC557B_J35Z requirements.

6.How does Aetrix verify that BC557B_J35Z is sourced from the original manufacturer or authorized distributors?

All BC557B_J35Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BC557B_J35Z meets industry standards.

7.What is the process for return or replacement of BC557B_J35Z?

All BC557B_J35Z units undergo pre-shipment inspection (PSI). If there is an issue with BC557B_J35Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BC557B_J35Z part is unused and in its original packaging.

Return procedure for BC557B_J35Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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