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

NXP Semiconductors BC557C,112

Name: BC557C,112
Brand: NXP Semiconductors
SKU: BC557C,112
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC557C,112

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

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

Datasheet:: BC557C,112.pdf

Description:: TRANS PNP 45V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC557C,112 from NXP Semiconductors is a PNP general-purpose bipolar junction transistor in TO-92 (SOT54) package, rated for −45 V V_CEO, −100 mA I_C, and 500 mW P_tot, with h_FE of 420–800 at I_C = −2 mA, used in low-voltage signal switching and linear amplification circuits.

For engineers reviewing the BC557C,112 datasheet, BC557C,112 pinout, BC557C,112 application, or BC557C,112 equivalent, key selection criteria include guaranteed h_FE range, V_CEsat ≤ −300 mV at I_C = −10 mA/I_B = −0.5 mA, thermal resistance of 250 K/W, and compatibility with through-hole PCB assembly.

Technical Context

The BC557C,112 operates as a silicon PNP BJT with base-controlled current amplification, optimized for DC and low-frequency AC operation up to 100 MHz f_T. Its design supports stable biasing in common-emitter configurations with V_BE = −650 mV typical at I_C = −2 mA.

It features low leakage (I_CBO ≤ −15 nA at T_j = 25 °C), low noise (F = 2–10 dB at 1 kHz), and defined saturation behavior (V_CEsat ≤ −650 mV at I_C = −100 mA), making it suitable for precision analog and reliable digital switching where gain consistency matters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V: Maximum collector-emitter voltage before breakdown in open-base configuration.
I_C (DC)	−100 mA: Continuous collector current rating defining safe linear/switching operation.
h_FE	420–800 at I_C = −2 mA, V_CE = −5 V: Guaranteed DC current gain range for predictable bias design.
V_CEsat	≤ −300 mV at I_C = −10 mA / I_B = −0.5 mA: Low saturation voltage ensures minimal power loss in switch mode.
R_th(j-a)	250 K/W: Thermal resistance from junction to ambient on FR4 PCB, critical for derating above 25 °C.
f_T	100 MHz: Transition frequency confirming usable bandwidth for audio and low-speed digital signals.

Pinout & Package

BC557C,112 is housed in a plastic single-ended leaded (through-hole) TO-92 package, also designated SOT54 or SC-43A, with 3 leads and standard 2.54 mm lead pitch.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit terminal; connected to most positive rail in PNP switching applications.
2	Base	Control input; requires negative bias relative to emitter to turn on device.
3	Collector	Current entry terminal; typically tied to load and ground-return path in common-emitter topology.

Key Features

Feature	Design Value
Guaranteed h_FE binning	BC557C variant ensures minimum h_FE of 420, reducing need for gain compensation in production designs.
Low V_CEsat	≤ −300 mV at light load enables efficient switching with <10 mW dissipation in saturated state.
Low noise figure	2–10 dB at 1 kHz supports use in preamplifier stages without significant SNR degradation.
Thermal stability	V_BE drift of −2 mV/K allows predictable bias shift over temperature in amplifier circuits.

Applications

Audio Pre-amplification	LED Driver Switch
Use Scenario: Amplifying microphone-level signals in portable audio recorders before ADC sampling. IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter amplifier with fixed bias network. Use Value: High h_FE (420–800) ensures sufficient voltage gain with minimal external components; low noise preserves signal integrity.	Use Scenario: Driving red/green indicator LEDs from microcontroller GPIO pins with active-low logic. IC Role / Device Role / Timing Role: Low-side switch with emitter tied to V_CC, collector to LED anode, base driven by MCU output. Use Value: V_CEsat ≤ −300 mV guarantees >95% LED forward voltage utilization; −100 mA rating supports multiple parallel LEDs.
Relay Driver Circuit	Level Translation Interface
Use Scenario: Controlling 5 V/12 V electromagnetic relays in industrial control panels using 3.3 V logic outputs. IC Role / Device Role / Timing Role: PNP switch in emitter-follower configuration to invert and level-shift control signal. Use Value: −45 V V_CEO safely handles relay coil flyback transients; robust I_CM = −200 mA withstands inductive kick.	Use Scenario: Interfacing 5 V legacy peripherals with 3.3 V microcontrollers in mixed-voltage embedded systems. IC Role / Device Role / Timing Role: Voltage-level shifter using PNP-based open-collector pull-up with base control. Use Value: Precise V_BE = −650 mV enables accurate threshold setting; low C_c = 3 pF minimizes signal delay distortion.

Audio Pre-amplification

LED Driver Switch

Use Scenario: Amplifying microphone-level signals in portable audio recorders before ADC sampling.

IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter amplifier with fixed bias network.

Use Value: High h_FE (420–800) ensures sufficient voltage gain with minimal external components; low noise preserves signal integrity.

Use Scenario: Driving red/green indicator LEDs from microcontroller GPIO pins with active-low logic.

IC Role / Device Role / Timing Role: Low-side switch with emitter tied to V_CC, collector to LED anode, base driven by MCU output.

Use Value: V_CEsat ≤ −300 mV guarantees >95% LED forward voltage utilization; −100 mA rating supports multiple parallel LEDs.

Relay Driver Circuit

Level Translation Interface

Use Scenario: Controlling 5 V/12 V electromagnetic relays in industrial control panels using 3.3 V logic outputs.

IC Role / Device Role / Timing Role: PNP switch in emitter-follower configuration to invert and level-shift control signal.

Use Value: −45 V V_CEO safely handles relay coil flyback transients; robust I_CM = −200 mA withstands inductive kick.

Use Scenario: Interfacing 5 V legacy peripherals with 3.3 V microcontrollers in mixed-voltage embedded systems.

IC Role / Device Role / Timing Role: Voltage-level shifter using PNP-based open-collector pull-up with base control.

Use Value: Precise V_BE = −650 mV enables accurate threshold setting; low C_c = 3 pF minimizes signal delay distortion.

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	h_FE = 220–475 (lower min/max gain); same V_CEO, V_CEsat, and package.	Suitable where lower gain tolerance is acceptable and cost optimization is prioritized.	Select BC557B,112 when circuit gain margin allows reduced h_FE spread and tighter BOM control is needed.
PN2907A	Same TO-92 package; V_CEO = −60 V (higher), h_FE = 100–300 (narrower, lower range), P_tot = 625 mW.	Better for higher-voltage switching but less suitable for high-gain linear amplification.	Choose PN2907A only if V_CEO > −45 V is required and gain consistency is secondary to voltage headroom.

Compared with BC557B,112 and PN2907A, BC557C,112 delivers the highest guaranteed h_FE floor (420) and tightest match to low-noise, medium-speed analog switching needs-making it optimal where gain predictability and signal fidelity are design-critical.

Availability

BC557C,112 is available at Aetrix Electronics and suitable for audio pre-amplification, LED driver switching, and relay driver circuits requiring stable component supply and consistent parametric performance across production batches.

Supply support for BC557C,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 BC557C,112 belongs to NXP's legacy discrete transistor portfolio, designed specifically for cost-sensitive, high-reliability general-purpose analog and switching functions in through-hole assembled equipment.

FAQ

What is the maximum collector-emitter voltage rating for BC557C,112?

The BC557C,112 has a maximum collector-emitter voltage (V_CEO) rating of −45 V under open-base conditions. This value defines the upper limit for safe DC operation in common-emitter configurations and must not be exceeded to prevent avalanche breakdown. Derating is recommended above +25 °C ambient per the thermal resistance specification.

Does BC557C,112 have a specified transition frequency (f_T)?

Yes, BC557C,112 has a minimum transition frequency (f_T) of 100 MHz, measured at V_CE = −5 V and I_C = −10 mA. This confirms its suitability for audio-frequency amplification and low-speed digital signal switching, though it is not intended for RF or high-speed switching applications beyond ~10 MHz practical bandwidth.

What is the guaranteed DC current gain (h_FE) range for BC557C,112?

The BC557C,112 is binned to guarantee h_FE between 420 and 800 when tested at I_C = −2 mA and V_CE = −5 V. This high-gain range distinguishes it from BC557A and BC557B variants and supports simplified bias network design in linear amplifier and precision switching applications.

Can BC557C,112 be used in surface-mount designs?

No, BC557C,112 is packaged exclusively in the through-hole TO-92 (SOT54) format and lacks surface-mount terminals. It requires plated-through holes and wave or hand soldering. For SMT equivalents, consider SOT-23 PNP transistors like MMBT2907A, which differ in gain, voltage, and thermal characteristics-not drop-in replacements for BC557C,112.

What is the thermal resistance (R_th(j-a)) of BC557C,112 and how is it measured?

The BC557C,112 has a thermal resistance from junction to ambient (R_th(j-a)) of 250 K/W, measured with the device mounted on a standard FR4 printed-circuit board per NXP's test condition. This value guides power derating: at +75 °C ambient, maximum allowable P_tot drops to 300 mW to maintain T_j ≤ 150 °C.

BC557C,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):: 45 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 420 @ 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

BC557C,112 FAQ

1.How can I place an order for BC557C,112 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC557C,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 BC557C,112 reliable?

The price and inventory of BC557C,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC557C,112 is usually 5 days.

3.What payment methods are accepted for BC557C,112?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC557C,112 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC557C,112?

BC557C,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC557C,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 BC557C,112?

For technical support, including BC557C,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC557C,112 requirements.

6.How does Aetrix verify that BC557C,112 is sourced from the original manufacturer or authorized distributors?

All BC557C,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 BC557C,112 meets industry standards.

7.What is the process for return or replacement of BC557C,112?

All BC557C,112 units undergo pre-shipment inspection (PSI). If there is an issue with BC557C,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 BC557C,112 part is unused and in its original packaging.

Return procedure for BC557C,112:

1.Submit a request within 90 days.

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

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