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

onsemi BC556BTAR

Name: BC556BTAR
Brand: onsemi
SKU: BC556BTAR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC556BTAR

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC556BTAR.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:4,601

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Product details

Overview

BC556BTAR 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, I_C = −100 mA, h_FE = 200–450 (Class B), V_CE(sat) ≤ −300 mV at I_C = −10 mA/I_B = −0.5 mA, and f_T = 150 MHz - enabling use in audio preamplifiers, relay drivers, and level-shifting interfaces.

For engineers reviewing the BC556BTAR datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92-3 (Case 135AR) package, complementary pairing with BC546–BC550 NPN series, −65 V breakdown rating, and Class B h_FE binning - critical for bias-stable analog gain stages and robust DC switching.

Technical Context

The BC556BTAR operates as a medium-voltage, medium-current PNP bipolar junction transistor with fixed-emitter configuration and base-controlled current amplification. Its design supports both active-region amplification (with h_FE validated at V_CE = −5 V, I_C = −2 mA) and saturated switching (with V_CE(sat) specified at two current levels).

Thermal performance is defined by R_JA = 250 °C/W on standard FR-4 PCB (76 mm × 114 mm), and it complies with RoHS, Pb-free, and halogen-free requirements. The device is not recommended for new designs per onsemi's discontinuation notice but remains supported for legacy production continuity.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−65 V: Maximum collector-emitter voltage before breakdown; enables use in 48 V rail switching and high-side load control.
I_C (DC)	−100 mA: Continuous collector current limit; suitable for driving LEDs, small relays, and logic-level translators.
h_FE (Class B)	200–450: Confirmed DC current gain range at V_CE = −5 V, I_C = −2 mA; ensures predictable biasing in amplifier bias networks.
V_CE(sat)	−300 mV max at I_C = −10 mA/I_B = −0.5 mA: Low saturation voltage reduces power loss and heat generation in switching mode.
f_T	150 MHz: Current gain bandwidth product at V_CE = −5 V, I_C = −10 mA; supports audio-frequency amplification and fast digital edge handling.
C_ob	6 pF at V_CB = −10 V: Output capacitance impacts high-frequency stability and bandwidth in tuned circuits.

Pinout & Package

BC556BTAR is housed in a TO-92-3 plastic package (Case 135AR), lead-formed, with standardized pin assignment when viewed from the flat side with leads downward: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Current sink terminal	Connected to higher-potential node (e.g., V_CC or load return); carries full output current in common-emitter configuration.
2 (Base)	Control input	Receives forward-biased current to enable conduction; requires external current-limiting resistor for safe drive.
3 (Emitter)	Reference terminal	Typically tied to circuit ground or positive rail in high-side switch; sets emitter-base voltage reference for biasing.

Key Features

Feature	Design Value
High-voltage PNP structure	V_CEO = −65 V supports operation in industrial 24–48 V systems without additional protection circuitry.
Class B h_FE binning	Guaranteed 200–450 gain range improves consistency across production batches in analog gain blocks.
Low-noise capability (shared family)	Specified NF = 2–10 dB at 1 kHz (BC556/557/558), making it suitable for microphone preamp front-ends where signal integrity matters.
Pb-free, RoHS-compliant packaging	TO-92-3 case 135AR meets global environmental compliance mandates for commercial and industrial PCB assembly.

Applications

Audio Preamp Stage	Relay Driver Circuit
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors in battery-powered voice recorders. IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing 20–40 dB voltage gain with minimal added noise. Use Value: Class B h_FE binning and 2–10 dB noise figure ensure stable gain and low self-noise in first-stage amplification.	Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and HVAC control panels. IC Role / Device Role / Timing Role: Saturated PNP switch controlling relay coil current with low V_CE(sat) to minimize power dissipation. Use Value: −300 mV max V_CE(sat) at −10 mA base drive reduces thermal stress and extends relay coil life.
Level-Shifting Interface	High-Side Load Switch
Use Scenario: Translating 3.3 V logic outputs to interface with 5 V or 12 V peripheral logic inputs in mixed-voltage embedded systems. IC Role / Device Role / Timing Role: Inverter-based level shifter using emitter-follower or common-emitter topology. Use Value: −65 V V_CEO and −100 mA I_C allow safe operation across wide supply margins without clamping diodes.	Use Scenario: Controlling power to sensors or actuators referenced to system ground in automotive body electronics. IC Role / Device Role / Timing Role: High-side PNP switch placing load between V_BAT and collector, with emitter tied to V_BAT. Use Value: Complementary pairing with BC546–BC550 simplifies dual-rail driver design and enables matched thermal behavior.

Audio Preamp Stage

Relay Driver Circuit

Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors in battery-powered voice recorders.

IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing 20–40 dB voltage gain with minimal added noise.

Use Value: Class B h_FE binning and 2–10 dB noise figure ensure stable gain and low self-noise in first-stage amplification.

Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and HVAC control panels.

IC Role / Device Role / Timing Role: Saturated PNP switch controlling relay coil current with low V_CE(sat) to minimize power dissipation.

Use Value: −300 mV max V_CE(sat) at −10 mA base drive reduces thermal stress and extends relay coil life.

Level-Shifting Interface

High-Side Load Switch

Use Scenario: Translating 3.3 V logic outputs to interface with 5 V or 12 V peripheral logic inputs in mixed-voltage embedded systems.

IC Role / Device Role / Timing Role: Inverter-based level shifter using emitter-follower or common-emitter topology.

Use Value: −65 V V_CEO and −100 mA I_C allow safe operation across wide supply margins without clamping diodes.

Use Scenario: Controlling power to sensors or actuators referenced to system ground in automotive body electronics.

IC Role / Device Role / Timing Role: High-side PNP switch placing load between V_BAT and collector, with emitter tied to V_BAT.

Use Value: Complementary pairing with BC546–BC550 simplifies dual-rail driver design and enables matched thermal behavior.

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), same h_FE Class B, identical TO-92-3 package	Not suitable for >45 V rail applications; preferred where lower voltage margin reduces risk of overvoltage failure	Select BC557BTA when system V_CC ≤ 36 V and tighter voltage derating is required.
BC856B, SOT-23	SMT package (SOT-23), same V_CEO/h_FE, lower I_C = −100 mA, higher R_JA = 375 °C/W	Enables space-constrained PCB layouts but requires thermal relief for >50 mA continuous operation	Choose BC856B for automated assembly and compact designs where board area is constrained.

Compared with BC556BTAR, BC557BTA offers reduced voltage rating for improved safety margin at lower cost, while BC856B provides surface-mount compatibility at the expense of thermal performance - both serve distinct layout and reliability trade-offs in PNP switching/amplifier roles.

Availability

BC556BTAR is available at Aetrix Electronics and suitable for audio signal conditioning, relay interfacing, level-shifting interfaces, and high-side load switching requiring stable component supply and legacy design continuity.

Supply support for BC556BTAR 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC556 series belongs to onsemi's legacy general-purpose bipolar transistor product line, engineered for cost-sensitive, high-reliability linear and switching functions in consumer, industrial, and communication equipment.

FAQ

What is the maximum collector-emitter voltage rating for BC556BTAR?

The BC556BTAR has a guaranteed V_CEO rating of −65 V at T_A = 25°C. This allows safe operation in circuits with up to 48 V supply rails with appropriate derating. Exceeding this voltage risks avalanche breakdown and permanent damage. The BC556BTAR datasheet specifies this value under absolute maximum ratings and confirms it applies specifically to the BC556 variant within the BC556–BC560 family.

Is BC556BTAR RoHS compliant and lead-free?

Yes, BC556BTAR is RoHS compliant, Pb-free, and halogen-free/BFR-free per onsemi's official datasheet revision 3 (June 2024). It uses lead-formed TO-92-3 packaging (Case 135AR) meeting EU Directive 2011/65/EU and related global environmental standards. This makes BC556BTAR suitable for commercial and industrial PCB assembly without exemption requests.

What does the "B" in BC556BTAR signify?

The "B" in BC556BTAR denotes the h_FE gain classification bin: 200–450 at V_CE = −5 V and I_C = −2 mA. This is distinct from "A" (110–220) and "C" (420–800) variants. The "TAR" suffix indicates tape-and-reel packaging in TO-92-3 (Case 135AR), confirming form factor and logistics format for automated placement.

Can BC556BTAR be used as a direct replacement for BC557BTA?

No - BC556BTAR is not a direct replacement for BC557BTA due to differing V_CEO ratings (−65 V vs. −45 V) and V_CBO (−80 V vs. −50 V). While both share the same TO-92-3 package and Class B h_FE, substituting BC556BTAR into a BC557BTA design may over-specify voltage capability but introduces unnecessary cost and potential reliability mismatch in lower-voltage systems.

What is the thermal resistance of BC556BTAR and how does it affect PCB layout?

BC556BTAR has a specified R_JA of 250 °C/W on a standard FR-4 PCB (76 mm × 114 mm, 1.57 mm thick) with minimum land pattern. This means junction temperature rises 250°C per watt dissipated - so at 300 mW power, ΔT ≈ 75°C above ambient. Layout must include adequate copper pour on the collector pad and avoid thermal isolation to prevent exceeding T_J = 150°C.

BC556BTAR Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

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:: 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

BC556BTAR FAQ

1.How can I place an order for BC556BTAR through Aetrix?

Please submit a Request for Quotation (RFQ) for BC556BTAR 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 BC556BTAR reliable?

The price and inventory of BC556BTAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC556BTAR is usually 5 days.

3.What payment methods are accepted for BC556BTAR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC556BTAR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC556BTAR?

BC556BTAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC556BTAR 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 BC556BTAR?

For technical support, including BC556BTAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC556BTAR requirements.

6.How does Aetrix verify that BC556BTAR is sourced from the original manufacturer or authorized distributors?

All BC556BTAR 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 BC556BTAR meets industry standards.

7.What is the process for return or replacement of BC556BTAR?

All BC556BTAR units undergo pre-shipment inspection (PSI). If there is an issue with BC556BTAR, 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 BC556BTAR part is unused and in its original packaging.

Return procedure for BC556BTAR:

1.Submit a request within 90 days.

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

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