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

onsemi BC556_J18Z

Name: BC556_J18Z
Brand: onsemi
SKU: BC556_J18Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC556_J18Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC556_J18Z.pdf

Description:: TRANS PNP 65V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC556_J18Z from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and linear amplification in low-to-medium power circuits. It features −65 V collector-emitter voltage (V_CEO), −100 mA DC collector current, 110–800 DC current gain (h_FE), and 150 MHz transition frequency (f_T). It is commonly used in audio preamplifiers, relay drivers, and level-shifting interfaces.

For engineers reviewing the BC556_J18Z datasheet, pinout, applications, or equivalent options, key selection criteria include its high-voltage PNP capability, TO-92 package compatibility, low-noise performance relative to BC557/BC558 variants, and complementarity with BC546–BC550 NPN series.

Technical Context

The BC556_J18Z operates as a standard bipolar junction transistor with fixed emitter-base and collector-base junctions optimized for stable DC biasing and moderate-frequency AC signal handling. Its h_FE classification (A/B/C) determines gain spread, and its −65 V V_CEO rating enables use in higher-voltage negative-rail circuits compared to BC557/BC558.

Thermal design relies on its 500 mW total device dissipation at 25°C, derating at 4.0 mW/°C above ambient, with a junction-to-ambient thermal resistance of 250°C/W on standard FR-4 PCB land patterns. Its 6 pF output capacitance (C_ob) supports operation up to ~150 MHz under specified test conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−65 V: Supports operation in negative-rail circuits up to 65 V without breakdown.
I_C (DC)	−100 mA: Sustained collector current capacity suitable for driving small relays or LEDs.
h_FE	110–800: Wide DC current gain range enabling flexible bias network design across variants.
f_T	150 MHz: Enables use in RF preamp stages or fast-switching applications up to mid-VHF.
V_CE(sat)	−90 to −650 mV: Low saturation voltage ensures efficient switching with minimal conduction loss.
C_ob	6 pF: Output capacitance limits high-frequency bandwidth but remains suitable for audio and low-RF designs.
NF	2–10 dB @ 1 kHz: Noise figure appropriate for low-level analog amplification where signal integrity matters.

Pinout & Package

BC556_J18Z is housed in a TO-92-3 plastic package (Case 135AR or 135AN), with standardized lead configuration: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter. The package is RoHS-compliant, Pb-free, and halogen-free.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Current sink terminal	Connected to negative supply rail or load return path in PNP common-emitter configurations.
2 (Base)	Control input	Receives reverse-biased current to turn on the transistor; requires current-limiting resistor in most applications.
3 (Emitter)	Current source terminal	Typically tied to positive supply in PNP switching; provides reference point for bias networks.

Key Features

Feature	Design Value
High-voltage PNP operation	−65 V V_CEO enables robustness in industrial control and legacy power supply rails.
Complementary pairing	Designed as direct PNP counterpart to BC546–BC550 NPN series for push-pull and differential stages.
Low-noise amplification	2–10 dB noise figure supports clean signal amplification in microphone preamps and sensor interfaces.
Pb-free & RoHS compliance	Meets global environmental standards without requiring process or layout changes for compliant manufacturing.

Applications

Audio Preamp Stage	Relay Driver Circuit
Use Scenario: Amplifying weak signals from dynamic microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Linear amplifier in common-emitter configuration with emitter degeneration for stability. Use Value: 150 MHz f_T and 2–10 dB NF ensure fidelity across 20 Hz–20 kHz band without added distortion.	Use Scenario: Switching 12 V/24 V electromagnetic relays in PLC I/O modules or HVAC controllers. IC Role / Device Role / Timing Role: Saturated switch controlling relay coil current with base-driven turn-on/turn-off. Use Value: −65 V V_CEO and −100 mA I_C safely handle relay back-EMF and steady-state coil current.
Level-Shifting Interface	Discrete Logic Inverter
Use Scenario: Translating logic levels between −5 V TTL and 0 V/3.3 V CMOS domains in mixed-supply systems. IC Role / Device Role / Timing Role: Active pull-up stage with emitter-follower or common-base topology. Use Value: −5 V V_EBO and precise V_BE(on) (−600 to −750 mV) enable predictable threshold behavior.	Use Scenario: Implementing NOT gates or signal inversion in discrete logic subsystems where ICs are unavailable or overqualified. IC Role / Device Role / Timing Role: Digital switch operating in cutoff/saturation with defined logic thresholds. Use Value: Fast switching due to low C_ob (6 pF) and sub-1 µs propagation delay supports >1 MHz toggle rates.

Audio Preamp Stage

Relay Driver Circuit

Use Scenario: Amplifying weak signals from dynamic microphones or piezoelectric sensors before ADC sampling.

IC Role / Device Role / Timing Role: Linear amplifier in common-emitter configuration with emitter degeneration for stability.

Use Value: 150 MHz f_T and 2–10 dB NF ensure fidelity across 20 Hz–20 kHz band without added distortion.

Use Scenario: Switching 12 V/24 V electromagnetic relays in PLC I/O modules or HVAC controllers.

IC Role / Device Role / Timing Role: Saturated switch controlling relay coil current with base-driven turn-on/turn-off.

Use Value: −65 V V_CEO and −100 mA I_C safely handle relay back-EMF and steady-state coil current.

Level-Shifting Interface

Discrete Logic Inverter

Use Scenario: Translating logic levels between −5 V TTL and 0 V/3.3 V CMOS domains in mixed-supply systems.

IC Role / Device Role / Timing Role: Active pull-up stage with emitter-follower or common-base topology.

Use Value: −5 V V_EBO and precise V_BE(on) (−600 to −750 mV) enable predictable threshold behavior.

Use Scenario: Implementing NOT gates or signal inversion in discrete logic subsystems where ICs are unavailable or overqualified.

IC Role / Device Role / Timing Role: Digital switch operating in cutoff/saturation with defined logic thresholds.

Use Value: Fast switching due to low C_ob (6 pF) and sub-1 µs propagation delay supports >1 MHz toggle rates.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC557BTA	V_CEO = −45 V; lower max voltage rating than BC556_J18Z.	Better suited for ≤45 V rail applications; not recommended where −65 V margin is required.	Select BC557BTA only when system voltage is confirmed ≤45 V and gain spread (200–450) matches design needs.
BC856BMTF	SOT-23 surface-mount package; same V_CEO (−65 V), h_FE (200–450), but lower I_C (−100 mA same, but smaller thermal mass).	Requires PCB redesign for SMT; preferred for space-constrained or automated assembly environments.	Choose BC856BMTF for new compact designs with reflow-compatible layouts; retain BC556_J18Z for through-hole prototyping or legacy repair.

Compared with BC557BTA and BC856BMTF, BC556_J18Z offers the highest voltage margin among through-hole PNP transistors in its family and maintains legacy TO-92 compatibility without sacrificing gain or noise performance - making it optimal for field-replaceable high-voltage analog or switching nodes.

Availability

BC556_J18Z is available at Aetrix Electronics and suitable for audio preamplifiers, relay driver circuits, and level-shifting interfaces requiring stable component supply and long-term obsolescence management.

Supply support for BC556_J18Z 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 manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The BC556_J18Z belongs to onsemi's legacy general-purpose bipolar transistor product line, engineered for reliability, wide temperature operation (−65°C to +150°C), and seamless integration into cost-sensitive analog and discrete logic circuits.

FAQ

What is the maximum collector-emitter voltage rating for BC556_J18Z?

The BC556_J18Z has a maximum collector-emitter voltage (V_CEO) rating of −65 V. This value is confirmed in the Absolute Maximum Ratings table of the official onsemi datasheet and defines the upper limit of reverse bias the transistor can withstand in common-emitter configuration without breakdown. Exceeding this rating risks permanent damage to BC556_J18Z.

Is BC556_J18Z RoHS-compliant and lead-free?

Yes, BC556_J18Z is RoHS-compliant and lead-free, as explicitly stated in the "Features" section of the onsemi datasheet. It also meets halogen-free and BFR-free requirements. This compliance applies to both TO-92-3 package variants (Case 135AR and 135AN) used for BC556_J18Z, ensuring BC556_J18Z meets global environmental directives for commercial and industrial use.

What is the typical DC current gain (h_FE) range for BC556_J18Z at V_CE = −5 V and I_C = −2 mA?

The typical DC current gain (h_FE) for BC556_J18Z ranges from 110 to 800 under the conditions V_CE = −5 V and I_C = −2 mA, per the Electrical Characteristics table. This wide spread reflects h_FE classification (A/B/C), and actual BC556_J18Z units will fall within one of these sub-ranges depending on factory binning - critical for bias stability in precision amplifier designs using BC556_J18Z.

Can BC556_J18Z be used as a direct replacement for BC557 in a circuit?

No, BC556_J18Z is not a direct replacement for BC557 due to differing absolute maximum ratings: BC556_J18Z supports −65 V V_CEO, while BC557 is rated for only −45 V. Substituting BC556_J18Z into a BC557-designed circuit is generally safe, but replacing BC556_J18Z with BC557 in a −60 V application risks failure. Always verify voltage margins before interchanging BC556_J18Z and BC557.

What package type and pin configuration does BC556_J18Z use?

BC556_J18Z uses the TO-92-3 plastic package (Case 135AR or 135AN), with standardized pinout: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter. This configuration is confirmed in the Marking Diagram and Mechanical Case Outline sections of the onsemi datasheet and is consistent across all BC556 variants, including BC556_J18Z.

BC556_J18Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 65 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 110 @ 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

BC556_J18Z FAQ

1.How can I place an order for BC556_J18Z through Aetrix?

Please submit a Request for Quotation (RFQ) for BC556_J18Z 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 BC556_J18Z reliable?

The price and inventory of BC556_J18Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC556_J18Z is usually 5 days.

3.What payment methods are accepted for BC556_J18Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC556_J18Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC556_J18Z?

BC556_J18Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC556_J18Z 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 BC556_J18Z?

For technical support, including BC556_J18Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC556_J18Z requirements.

6.How does Aetrix verify that BC556_J18Z is sourced from the original manufacturer or authorized distributors?

All BC556_J18Z 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 BC556_J18Z meets industry standards.

7.What is the process for return or replacement of BC556_J18Z?

All BC556_J18Z units undergo pre-shipment inspection (PSI). If there is an issue with BC556_J18Z, 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 BC556_J18Z part is unused and in its original packaging.

Return procedure for BC556_J18Z:

1.Submit a request within 90 days.

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

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