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

onsemi BC556TF

Name: BC556TF
Brand: onsemi
SKU: BC556TF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC556TF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC556TF.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC556TF 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 breakdown voltage (V_CEO), 110–800 DC current gain (h_FE), −100 mA continuous collector current, TO-92-3 package (case 135AR), and RoHS-compliant Pb-free construction. It serves as a complement to BC546–BC550 NPN transistors in dual-polarity designs such as audio preamplifiers and relay drivers.

For engineers reviewing the BC556TF datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO = −65 V, h_FE classification (B-grade), saturation voltage at −10 mA/−0.5 mA bias, thermal resistance of 250 °C/W, and TO-92 leadform compatibility with automated tape-and-reel assembly.

Technical Context

This device operates as a medium-voltage, low-noise PNP bipolar junction transistor optimized for DC-coupled amplification and saturated switching. Its −80 V V_CBO, −5 V V_EBO, and 150 MHz f_T support stable operation in analog signal paths up to mid-audio frequencies and fast digital edge control.

Thermal design relies on its 500 mW total dissipation rating with 4.0 mW/°C derating above 25°C ambient, and junction temperature limit of 150°C ensures reliability in enclosed industrial enclosures. The 6 pF output capacitance (C_ob) minimizes high-frequency loading in multi-stage amplifier feedback networks.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−65 V: Maximum safe collector-emitter reverse voltage before breakdown in common-emitter configuration.
h_FE (B-grade)	200–450: Confirmed DC current gain range at V_CE = −5 V, I_C = −2 mA - enables predictable biasing in Class-A amplifiers.
V_CE(sat)	−90 to −300 mV: Verified saturation voltage at I_C = −10 mA / I_B = −0.5 mA - ensures low conduction loss in switch-mode applications.
f_T	150 MHz: Current gain bandwidth product at V_CE = −5 V, I_C = −10 mA - supports stable small-signal amplification up to ~10 MHz.
R_JA	250 °C/W: Junction-to-ambient thermal resistance on standard FR-4 PCB - defines minimum copper area needed for 500 mW operation.
C_ob	6 pF: Output capacitance at V_CB = −10 V - limits high-frequency roll-off and phase shift in tuned circuits.

Pinout & Package

BC556TF uses the TO-92-3 package (case 135AR), a molded epoxy through-hole package with 4.83 mm × 4.76 mm footprint and leadformed terminals for tape-and-reel automated insertion.

Pin/Terminal	Circuit Role	Design Meaning
1 (Top View, Flat Side Up)	Collector	Main current sink terminal; connects to load or supply rail in common-emitter switching configurations.
2	Base	Control input; requires current-limited drive (e.g., via 10 kΩ resistor) to achieve full saturation or linear bias.
3	Emitter	Current source terminal; typically tied to positive rail in PNP switching or grounded in common-emitter amplifier topologies.

Key Features

Feature	Design Value
High-voltage PNP operation	V_CEO = −65 V enables use in 48 V industrial control rails and negative-supply analog stages without derating.
Low-noise amplification	Noise figure of 2–10 dB at 1 kHz (IC = −200 µA) supports clean signal conditioning in sensor front-ends.
Pb-free & RoHS compliance	Meets EU Directive 2011/65/EU and halogen-free/BFR-free requirements for environmentally regulated end equipment.
Complementary pairing	Engineered as direct PNP counterpart to BC546–BC550 series - simplifies dual-rail amplifier and push-pull stage design.

Applications

Audio Preamp Stage	Relay Driver Circuit
Use Scenario: Low-gain, single-transistor voltage amplifier for electret microphone biasing and signal buffering in battery-powered voice recorders. IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing 20–30 dB voltage gain with minimal component count and no DC blocking capacitors. Use Value: Leverages BC556TF's 200–450 h_FE and −600 to −750 mV V_BE(on) for stable quiescent point setting across temperature.	Use Scenario: Driving 12 V, 40 mA coil relays from microcontroller GPIO pins in HVAC control panels. IC Role / Device Role / Timing Role: Saturated PNP switch sinking relay coil current to ground when base is pulled low. Use Value: Uses BC556TF's −300 mV V_CE(sat) at −10 mA to minimize power loss and heat rise during continuous duty cycling.
LED Current Sink	Negative Rail Voltage Shifter
Use Scenario: Constant-current LED driver for status indicators in telecom line cards operating from −5 V supplies. IC Role / Device Role / Timing Role: Emitter-follower configured PNP regulating LED current via base voltage reference. Use Value: Relies on BC556TF's −5 V V_EBO rating and −100 mA I_C capability to safely handle 20 mA LED loads with margin.	Use Scenario: Level-shifting logic signals from 3.3 V microcontrollers to −5 V analog subsystems in test instrumentation. IC Role / Device Role / Timing Role: Inverting level translator using BC556TF in common-base configuration with pull-up to negative rail. Use Value: Exploits BC556TF's −80 V V_CBO and 150 MHz f_T to preserve signal integrity up to 1 MHz without added propagation delay.

Audio Preamp Stage

Relay Driver Circuit

Use Scenario: Low-gain, single-transistor voltage amplifier for electret microphone biasing and signal buffering in battery-powered voice recorders.

IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing 20–30 dB voltage gain with minimal component count and no DC blocking capacitors.

Use Value: Leverages BC556TF's 200–450 h_FE and −600 to −750 mV V_BE(on) for stable quiescent point setting across temperature.

Use Scenario: Driving 12 V, 40 mA coil relays from microcontroller GPIO pins in HVAC control panels.

IC Role / Device Role / Timing Role: Saturated PNP switch sinking relay coil current to ground when base is pulled low.

Use Value: Uses BC556TF's −300 mV V_CE(sat) at −10 mA to minimize power loss and heat rise during continuous duty cycling.

LED Current Sink

Negative Rail Voltage Shifter

Use Scenario: Constant-current LED driver for status indicators in telecom line cards operating from −5 V supplies.

IC Role / Device Role / Timing Role: Emitter-follower configured PNP regulating LED current via base voltage reference.

Use Value: Relies on BC556TF's −5 V V_EBO rating and −100 mA I_C capability to safely handle 20 mA LED loads with margin.

Use Scenario: Level-shifting logic signals from 3.3 V microcontrollers to −5 V analog subsystems in test instrumentation.

IC Role / Device Role / Timing Role: Inverting level translator using BC556TF in common-base configuration with pull-up to negative rail.

Use Value: Exploits BC556TF's −80 V V_CBO and 150 MHz f_T to preserve signal integrity up to 1 MHz without added propagation delay.

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
BC557BTF	V_CEO = −45 V; lower voltage rating than BC556TF's −65 V; otherwise identical h_FE B-grade and TO-92-3 packaging.	Suitable only where system rail voltages remain ≤ −40 V; not recommended for −48 V telecom or industrial backplanes.	Select BC557BTF only if design operates below −40 V and cost sensitivity outweighs voltage margin.
MMBT5551LT1G	PNP complement to MMBT5401; higher V_CEO (−60 V), SOT-23 surface-mount package, 200–450 h_FE range, but lower I_C (−150 mA).	Requires PCB redesign for SMT placement; better suited for space-constrained portable devices than through-hole legacy systems.	Choose MMBT5551LT1G only when board real estate is constrained and reflow assembly is available.

Compared with BC557BTF and MMBT5551LT1G, BC556TF provides the highest V_CEO among TO-92 PNP transistors in its family and maintains legacy through-hole compatibility without sacrificing h_FE performance or thermal robustness.

Availability

BC556TF is available at Aetrix Electronics and suitable for audio preamplifiers, relay driver circuits, LED current sinks, and negative-rail voltage shifters requiring stable component supply and long-term industrial availability.

Supply support for BC556TF 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 BC556TF belongs to onsemi's legacy general-purpose bipolar transistor family, engineered for reliability and consistency in cost-sensitive, high-volume analog and switching applications across consumer and industrial markets.

FAQ

What is the maximum collector-emitter voltage rating for BC556TF?

The BC556TF 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 nominal rails while maintaining ≥30% voltage margin. Exceeding this rating risks avalanche breakdown and permanent degradation of the BC556TF junction integrity.

Is BC556TF compatible with automated tape-and-reel assembly?

Yes, BC556TF is supplied in tape-and-reel format (TO-92-3, case 135AR) and is fully compatible with standard pick-and-place equipment. Its leadformed terminals and consistent orientation per reel meet IPC-7351 requirements, enabling reliable placement without manual rework or orientation verification for the BC556TF.

What h_FE range does BC556TF exhibit, and how is it classified?

The BC556TF is h_FE Class B, with a specified DC current gain range of 200–450 at V_CE = −5 V and I_C = −2 mA. This classification is laser-marked as "BC556B" on the device body and confirmed in onsemi's ordering matrix - critical for bias stability in linear amplifier designs using BC556TF.

Does BC556TF support low-noise audio applications?

Yes, BC556TF delivers a noise figure of 2–10 dB at 1 kHz with I_C = −200 µA, making it suitable for low-level signal amplification in microphone preamps and sensor interfaces. While BC559/BC560 offer lower noise, BC556TF balances noise performance with higher voltage capability - a key advantage in BC556TF-based audio front-ends.

How does BC556TF compare to BC546–BC550 NPN transistors in circuit design?

BC556TF is explicitly engineered as the PNP complement to the BC546–BC550 NPN series, sharing matching h_FE grading, thermal characteristics, and TO-92 packaging. This enables symmetrical push-pull output stages, dual-rail bias networks, and matched differential pairs - all using the same footprint and thermal management strategy for BC556TF and its NPN counterparts.

BC556TF Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

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

BC556TF FAQ

1.How can I place an order for BC556TF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC556TF 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 BC556TF reliable?

The price and inventory of BC556TF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC556TF is usually 5 days.

3.What payment methods are accepted for BC556TF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC556TF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC556TF?

BC556TF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC556TF 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 BC556TF?

For technical support, including BC556TF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC556TF requirements.

6.How does Aetrix verify that BC556TF is sourced from the original manufacturer or authorized distributors?

All BC556TF 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 BC556TF meets industry standards.

7.What is the process for return or replacement of BC556TF?

All BC556TF units undergo pre-shipment inspection (PSI). If there is an issue with BC556TF, 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 BC556TF part is unused and in its original packaging.

Return procedure for BC556TF:

1.Submit a request within 90 days.

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

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