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

onsemi BC556ABU

Name: BC556ABU
Brand: onsemi
SKU: BC556ABU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC556ABU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC556ABU.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC556ABU from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and linear amplification in low-to-medium power circuits. It features V_CEO = −65 V, h_FE = 110–220 (Class A), I_C = −100 mA DC, and V_BE(on) = −600 to −750 mV at I_C = −2 mA - enabling robust operation in bias-stable amplifier stages and relay drivers.

For engineers reviewing the BC556ABU datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92-3 (case 135AN) package, −65 V collector-emitter breakdown, Class A h_FE range, low-noise capability relative to BC556-series siblings, and complementarity to BC546–BC550 NPN transistors in push-pull designs.

Technical Context

The BC556ABU operates as a medium-voltage, medium-current PNP bipolar junction transistor with fixed gain classification (h_FE 110–220). Its V_CBO = −80 V and T_J = 150 °C support reliable operation in industrial control and analog signal conditioning where negative rail handling and thermal margin are critical.

It exhibits f_T = 150 MHz at V_CE = −5 V, I_C = −10 mA, confirming suitability for audio-frequency amplification and low-speed switching. Cob = 6 pF at V_CB = −10 V ensures minimal Miller effect in common-emitter configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−65 V: Maximum safe collector-emitter reverse voltage before breakdown; enables use in −48 V telecom or −24 V industrial logic interfaces.
h_FE (Class A)	110–220: Confirmed DC current gain range at V_CE = −5 V, I_C = −2 mA; supports predictable biasing in emitter-follower and common-emitter amplifiers.
I_C (DC)	−100 mA: Continuous collector current rating; sufficient for driving LEDs, small relays, or pre-driver stages without forced cooling.
V_BE(on)	−600 to −750 mV at I_C = −2 mA: Verified base-emitter turn-on threshold; allows accurate calculation of base resistor values in saturated switch applications.
f_T	150 MHz: Current gain bandwidth product at specified conditions; confirms usable gain up to mid-audio frequencies with stable phase margin.
C_ob	6 pF at V_CB = −10 V: Output capacitance limiting high-frequency response; critical for stability analysis in RF-coupled or wideband amplifier designs.

Pinout & Package

BC556ABU is housed in a TO-92-3 plastic package (case 135AN), with standard lead configuration: flat side facing viewer, leads downward, left-to-right pin order 1–2–3 corresponding to Collector–Base–Emitter.

Pin/Terminal	Circuit Role	Design Meaning
1	Collector	Main current sink terminal; connects to most negative supply rail or load return path in PNP switching topologies.
2	Base	Control input; requires current-limited drive (e.g., via series resistor) to achieve saturation or linear operation.
3	Emitter	Current source terminal; typically tied to system ground or positive rail in high-side switch configurations.

Key Features

Feature	Design Value
High-voltage PNP structure	V_CEO = −65 V enables direct interface with −48 V telecom systems or industrial −24 V control buses without level-shifting.
Class A h_FE binning	Guaranteed 110–220 gain range simplifies bias network design and improves batch consistency in production amplifiers.
Low noise performance	NF = 2–10 dB at 1 kHz (BC556/557/558 group) supports clean signal amplification in sensor front-ends and audio preamps.
Pb-free, RoHS-compliant	Meets global environmental regulations; eliminates lead-based solder compatibility concerns in modern assembly lines.

Applications

Audio Pre-amplifier Stage	Industrial Relay Driver
Use Scenario: Amplifying low-level microphone or piezoelectric sensor signals in battery-powered instrumentation. IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing voltage gain and impedance transformation. Use Value: Class A h_FE binning and low 2–10 dB noise figure ensure consistent signal integrity and minimal added distortion.	Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules or HVAC controllers. IC Role / Device Role / Timing Role: Saturated PNP switch controlling relay coil current with fast turn-off via base discharge path. Use Value: −65 V V_CEO withstands inductive kickback; −100 mA I_C rating covers typical 40–80 mA relay coils.
Complementary Push-Pull Output	Negative Rail Interface Circuit
Use Scenario: Paired with BC546A/B/C NPN transistors in Class AB audio output stages or precision op-amp output buffers. IC Role / Device Role / Timing Role: PNP half of complementary pair delivering current during negative half-cycle of AC signal. Use Value: Matched thermal characteristics and complementary h_FE ranges reduce crossover distortion and improve linearity.	Use Scenario: Level-shifting and signal inversion in −5 V or −12 V subsystems interfacing with 3.3 V/5 V microcontrollers. IC Role / Device Role / Timing Role: Inverting level translator and current buffer for digital control signals referenced to negative rails. Use Value: V_CBO = −80 V and V_CEO = −65 V allow safe operation across full negative supply swing without clamping diodes.

Audio Pre-amplifier Stage

Industrial Relay Driver

Use Scenario: Amplifying low-level microphone or piezoelectric sensor signals in battery-powered instrumentation.

IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing voltage gain and impedance transformation.

Use Value: Class A h_FE binning and low 2–10 dB noise figure ensure consistent signal integrity and minimal added distortion.

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

IC Role / Device Role / Timing Role: Saturated PNP switch controlling relay coil current with fast turn-off via base discharge path.

Use Value: −65 V V_CEO withstands inductive kickback; −100 mA I_C rating covers typical 40–80 mA relay coils.

Complementary Push-Pull Output

Negative Rail Interface Circuit

Use Scenario: Paired with BC546A/B/C NPN transistors in Class AB audio output stages or precision op-amp output buffers.

IC Role / Device Role / Timing Role: PNP half of complementary pair delivering current during negative half-cycle of AC signal.

Use Value: Matched thermal characteristics and complementary h_FE ranges reduce crossover distortion and improve linearity.

Use Scenario: Level-shifting and signal inversion in −5 V or −12 V subsystems interfacing with 3.3 V/5 V microcontrollers.

IC Role / Device Role / Timing Role: Inverting level translator and current buffer for digital control signals referenced to negative rails.

Use Value: V_CBO = −80 V and V_CEO = −65 V allow safe operation across full negative supply swing without clamping diodes.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC556ATA	Same electrical specs and h_FE Class A binning; differs only in TO-92-3 case 135AR (lead-formed) vs. 135AN (straight-lead) packaging.	Identical functional behavior; 135AR supports automated tape-and-reel placement; 135AN suits manual or bulk-insertion assembly.	Select BC556ATA for SMT production; BC556ABU for through-hole prototyping or low-volume hand-soldered builds.
BC557ABU	V_CEO = −45 V (vs. −65 V); otherwise identical h_FE Class A range, package, and pinout.	Not suitable for −48 V or high-voltage industrial rails; limited to ≤−36 V applications where lower breakdown suffices.	Choose BC557ABU only when system voltage constraints permit reduced headroom; retain BC556ABU for maximum voltage margin.

Compared with BC556ATA and BC557ABU, the BC556ABU uniquely combines −65 V V_CEO, Class A h_FE, and straight-lead TO-92-3 (135AN) packaging - making it optimal for through-hole designs requiring highest voltage tolerance and manual assembly compatibility.

Availability

BC556ABU is available at Aetrix Electronics and suitable for industrial control systems, audio signal conditioning circuits, and relay driver modules requiring stable component supply and long-term manufacturability.

Supply support for BC556ABU 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, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BC556ABU belongs to onsemi's legacy BC5xx PNP/NPN transistor family, engineered for cost-sensitive, high-reliability general-purpose analog and switching applications across consumer, industrial, and communications equipment.

FAQ

What is the maximum collector-emitter voltage rating for BC556ABU?

The BC556ABU has a guaranteed V_CEO rating of −65 V at T_A = 25 °C. This specifies the maximum reverse voltage the transistor can withstand between collector and emitter with the base open. Exceeding this value risks avalanche breakdown and permanent damage. Derating applies above 25 °C per the datasheet's thermal characteristics table.

Is BC556ABU pin-compatible with BC546 series NPN transistors?

Yes - the BC556ABU shares identical TO-92-3 (case 135AN) physical packaging and pinout (C-B-E) with BC546ABU and other BC54x NPN devices. This enables direct complementary pairing in push-pull, differential, or mirror circuits without PCB layout changes, provided voltage and current requirements align.

What does the 'A' suffix in BC556ABU indicate?

The 'A' in BC556ABU denotes h_FE classification: DC current gain falls within 110–220 at V_CE = −5 V and I_C = −2 mA. This binning ensures predictable bias point stability across production lots, distinguishing it from BC556B (200–450) and BC556C (420–800) variants.

Can BC556ABU be used in low-noise audio amplifier designs?

Yes - the BC556ABU belongs to the BC556/557/558 group rated for NF = 2–10 dB at 1 kHz (RG = 2 kΩ), making it suitable for low-noise pre-amplifier stages. Its noise performance is superior to BC559/560 but less optimized than dedicated low-noise transistors; verify against target SNR in final circuit simulation.

What is the thermal resistance junction-to-ambient for BC556ABU?

The BC556ABU has R_JA = 250 °C/W under standard FR-4 PCB conditions (76 mm × 114 mm, minimum land pattern). This value assumes natural convection; actual thermal performance depends on copper area, airflow, and board stack-up. For continuous −100 mA operation, junction temperature rise must remain below 150 °C.

BC556ABU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Active

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

BC556ABU FAQ

1.How can I place an order for BC556ABU through Aetrix?

Please submit a Request for Quotation (RFQ) for BC556ABU 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 BC556ABU reliable?

The price and inventory of BC556ABU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC556ABU is usually 5 days.

3.What payment methods are accepted for BC556ABU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC556ABU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC556ABU?

BC556ABU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC556ABU 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 BC556ABU?

For technical support, including BC556ABU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC556ABU requirements.

6.How does Aetrix verify that BC556ABU is sourced from the original manufacturer or authorized distributors?

All BC556ABU 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 BC556ABU meets industry standards.

7.What is the process for return or replacement of BC556ABU?

All BC556ABU units undergo pre-shipment inspection (PSI). If there is an issue with BC556ABU, 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 BC556ABU part is unused and in its original packaging.

Return procedure for BC556ABU:

1.Submit a request within 90 days.

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

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