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

NXP Semiconductors BC556B,112

Name: BC556B,112
Brand: NXP Semiconductors
SKU: BC556B,112
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC556B,112

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

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

Datasheet:: BC556B,112.pdf

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

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Product details

Overview

BC556B,112 from NXP Semiconductors is a PNP general-purpose bipolar junction transistor in TO-92 (SOT54) package, rated for −65 V V_CEO, −80 V V_CBO, −100 mA I_C, 500 mW P_tot, and featuring h_FE of 220–475 at I_C = −2 mA. It serves as a low-voltage, low-current switch or small-signal amplifier in discrete analog and digital interface circuits.

For engineers reviewing the BC556B,112 datasheet, BC556B,112 pinout, BC556B,112 application, or BC556B,112 equivalent, key selection criteria include verified PNP polarity, TO-92 mechanical compatibility, DC current gain range under −2 mA/−5 V bias, saturation voltage at −10 mA/−0.5 mA drive, and thermal resistance of 250 K/W on FR4 PCB.

Technical Context

The BC556B,112 operates as a silicon PNP BJT with fixed emitter-base-collector terminal assignment and no integrated biasing or protection. Its gain profile is specified across I_C = −0.1 mA to −100 mA at T_amb = 25 °C, with h_FE minimum of 220 at −2 mA/−5 V - distinct from BC556A (125–250) and BC557C (420–800).

It exhibits V_CEsat ≤ −300 mV at −10 mA/−0.5 mA and ≤ −650 mV at −100 mA/−5 mA, with V_BEsat ≤ −750 mV and V_BE ≈ −650 mV at −2 mA/−5 V. Junction temperature is rated to 150 °C, and storage ambient spans −65 °C to +150 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−65 V: Maximum collector-emitter voltage with base open; defines safe switching window in low-voltage PNP logic or load-switching applications.
h_FE	220–475 at I_C = −2 mA, V_CE = −5 V: Confirmed DC current gain range enabling predictable base drive sizing for amplification or saturated switching.
V_CEsat	≤ −300 mV at I_C = −10 mA, I_B = −0.5 mA: Ensures low conduction loss when used as an active low-side switch or level shifter.
P_tot	500 mW at T_amb ≤ 25 °C: Power dissipation limit requiring thermal derating above ambient; compatible with standard through-hole PCB layout without heatsink.
R_th(j-a)	250 K/W on FR4 board: Thermal resistance determines junction temperature rise per watt; supports continuous operation up to ~120 °C junction at 200 mW.
f_T	100 MHz: Transition frequency confirms usable bandwidth for audio-frequency amplification and low-speed digital signal conditioning.

Pinout & Package

BC556B,112 is housed in a plastic single-ended leaded (through-hole) TO-92 package, also designated SOT54 or SC-43A, with 3 leads and standardized mechanical dimensions per IEC/JEDEC outlines.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current source terminal in PNP configuration; connected to higher potential rail in common-emitter or common-base topologies.
2	Base	Control input; negative current injection turns device ON; requires series resistor to limit I_B within −200 mA peak rating.
3	Collector	Current sink terminal; connects to load or next stage; reverse-biased relative to emitter during OFF state.

Key Features

Feature	Design Value
PNP polarity	Enables complementary use with NXP's BC546/BC547 NPN transistors in push-pull, differential pair, or mirror configurations.
TO-92 package	Supports manual soldering and prototyping; compatible with standard breadboards and through-hole PCB footprints (SOT54 outline).
Low saturation voltage	V_CEsat ≤ −300 mV at light load ensures minimal voltage drop and power loss in linear regulator pass elements or LED driver switches.
Controlled h_FE binning	BC556B variant guarantees 220–475 h_FE, reducing design margin uncertainty compared to un-binned general-purpose transistors.

Applications

Audio Signal Amplification	Discrete Logic Level Shifting
Use Scenario: Amplifying microphone or line-level signals in battery-powered portable audio preamps. IC Role / Device Role / Timing Role: Small-signal PNP amplifier in common-emitter configuration with emitter degeneration. Use Value: 100 MHz f_T and stable h_FE support flat gain response up to 20 kHz; V_CEsat < −300 mV preserves headroom in single-supply designs.	Use Scenario: Translating 5 V TTL logic outputs to −5 V or −12 V referenced control signals in mixed-rail systems. IC Role / Device Role / Timing Role: Active-low level shifter using PNP emitter-follower or common-base topology. Use Value: Verified V_EB = −5 V rating and −100 nA I_EBO ensure reliable turn-off; TO-92 footprint simplifies integration with DIP logic ICs.
Relay Driver Circuit	Current Mirror Reference
Use Scenario: Driving 12 V/50 mA electromagnetic relay coils from microcontroller GPIO pins. IC Role / Device Role / Timing Role: Saturated PNP switch with base resistor limiting I_B to achieve forced β ≥ 10. Use Value: −65 V V_CEO withstands relay coil flyback spikes; −650 mV V_CEsat at −100 mA ensures < 65 mW coil dissipation loss.	Use Scenario: Building matched two-transistor current mirrors in analog sensor front-ends or bias networks. IC Role / Device Role / Timing Role: Reference leg of PNP current mirror where h_FE matching and low V_BE drift are critical. Use Value: −2 mV/K V_BE tempco and tight h_FE binning (220–475) improve mirror accuracy; −1 nA I_CBO minimizes error current at room temperature.

Audio Signal Amplification

Discrete Logic Level Shifting

Use Scenario: Amplifying microphone or line-level signals in battery-powered portable audio preamps.

IC Role / Device Role / Timing Role: Small-signal PNP amplifier in common-emitter configuration with emitter degeneration.

Use Value: 100 MHz f_T and stable h_FE support flat gain response up to 20 kHz; V_CEsat < −300 mV preserves headroom in single-supply designs.

Use Scenario: Translating 5 V TTL logic outputs to −5 V or −12 V referenced control signals in mixed-rail systems.

IC Role / Device Role / Timing Role: Active-low level shifter using PNP emitter-follower or common-base topology.

Use Value: Verified V_EB = −5 V rating and −100 nA I_EBO ensure reliable turn-off; TO-92 footprint simplifies integration with DIP logic ICs.

Relay Driver Circuit

Current Mirror Reference

Use Scenario: Driving 12 V/50 mA electromagnetic relay coils from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Saturated PNP switch with base resistor limiting I_B to achieve forced β ≥ 10.

Use Value: −65 V V_CEO withstands relay coil flyback spikes; −650 mV V_CEsat at −100 mA ensures < 65 mW coil dissipation loss.

Use Scenario: Building matched two-transistor current mirrors in analog sensor front-ends or bias networks.

IC Role / Device Role / Timing Role: Reference leg of PNP current mirror where h_FE matching and low V_BE drift are critical.

Use Value: −2 mV/K V_BE tempco and tight h_FE binning (220–475) improve mirror accuracy; −1 nA I_CBO minimizes error current at room temperature.

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
BC557B,112	Lower V_CEO (−45 V vs −65 V), same h_FE range (220–475), identical TO-92 package and pinout.	Suitable only where collector voltage remains ≤ −45 V; not interchangeable in −65 V designs.	Select BC557B,112 only if system V_CC is ≤ 45 V and cost or stock availability favors it.
PN2907A	Same TO-92 package, but h_FE = 100–300 (lower max), V_CEO = −60 V, P_tot = 400 mW (reduced power handling).	Marginally lower gain and power rating may require redesign of base drive or thermal layout.	Use PN2907A only when BC556B,112 is unavailable and circuit tolerates reduced h_FE and 100 mW lower dissipation.

Compared with BC556B,112, BC557B,112 offers identical gain but lower voltage rating, while PN2907A trades gain headroom and thermal capability for broader legacy availability - both require validation against original bias and stress conditions.

Availability

BC556B,112 is available at Aetrix Electronics and suitable for audio preamplifiers, relay drivers, discrete logic interfaces, and current mirror reference circuits requiring stable component supply and long-term industrial availability.

Supply support for BC556B,112 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and consumer applications.

The BC556 series belongs to NXP's legacy general-purpose transistor product line, designed specifically for cost-sensitive, reliability-critical discrete analog and switching functions in through-hole assembled equipment.

FAQ

What is the maximum collector-emitter voltage rating for BC556B,112?

The BC556B,112 has a maximum collector-emitter voltage (V_CEO) rating of −65 V with the base open. This absolute maximum rating must not be exceeded under any operating condition to prevent permanent device damage. Derating is required at elevated temperatures per the thermal characteristics table in the official NXP datasheet.

Is BC556B,112 pin-compatible with BC557B,112?

Yes, BC556B,112 and BC557B,112 share identical TO-92 (SOT54) package dimensions, pin numbering (emitter-base-collector on pins 1-2-3), and mechanical footprint. However, they differ in V_CEO (−65 V vs −45 V) and V_CBO (−80 V vs −50 V), so electrical substitution requires verification of voltage stress margins in the target circuit.

What is the typical DC current gain (h_FE) range for BC556B,112 at I_C = −2 mA?

The BC556B,112 exhibits a guaranteed h_FE range of 220 to 475 when tested at I_C = −2 mA and V_CE = −5 V, per the NXP product data sheet. This binning distinguishes it from BC556A (125–250) and BC557C (420–800), supporting consistent base resistor calculation across production units.

Can BC556B,112 be used in surface-mount designs?

No, BC556B,112 is a through-hole device in TO-92 (SOT54) package and is not suitable for standard SMT assembly. For surface-mount equivalents, consider NXP's PNP alternatives like PBSS4041T (SOT23) or MMBT3906 (SOT23), which differ in gain, voltage, and thermal performance - direct replacement requires full requalification.

What is the thermal resistance from junction to ambient for BC556B,112?

The BC556B,112 has a thermal resistance R_th(j-a) of 250 K/W when mounted on a standard FR4 printed-circuit board, as specified in the NXP datasheet. This value assumes natural convection cooling and defines the junction temperature rise per watt of dissipated power - critical for reliability assessment in continuous-conduction applications.

BC556B,112 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

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):: 65 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 220 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC556B,112 FAQ

1.How can I place an order for BC556B,112 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC556B,112 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 BC556B,112 reliable?

The price and inventory of BC556B,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC556B,112 is usually 5 days.

3.What payment methods are accepted for BC556B,112?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC556B,112 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC556B,112?

BC556B,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC556B,112 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 BC556B,112?

For technical support, including BC556B,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC556B,112 requirements.

6.How does Aetrix verify that BC556B,112 is sourced from the original manufacturer or authorized distributors?

All BC556B,112 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 BC556B,112 meets industry standards.

7.What is the process for return or replacement of BC556B,112?

All BC556B,112 units undergo pre-shipment inspection (PSI). If there is an issue with BC556B,112, 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 BC556B,112 part is unused and in its original packaging.

Return procedure for BC556B,112:

1.Submit a request within 90 days.

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

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