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

NXP Semiconductors BC549C,112

Name: BC549C,112
Brand: NXP Semiconductors
SKU: BC549C,112
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC549C,112

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

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

Datasheet:: BC549C,112.pdf

Description:: TRANS NPN 30V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC549C,112 from NXP Semiconductors is an NPN general-purpose bipolar junction transistor in TO-92 (SOT54/SC-43A) package, rated for 30 V V_CEO, 100 mA I_C, and 500 mW P_tot, optimized for low-noise audio amplification stages.

For engineers reviewing the BC549C,112 datasheet, BC549C,112 pinout, BC549C,112 application, or BC549C,112 equivalent, key selection criteria include h_FE range (420–800 at I_C = 2 mA), V_CEsat ≤ 250 mV at I_C = 10 mA, noise figure ≤ 4 dB, thermal resistance of 250 K/W, and TO-92 mechanical compatibility.

Technical Context

The BC549C,112 operates as a linear amplifying device with DC current gain specified across collector currents from 10 μA to 100 mA, featuring a transition frequency f_T of 100 MHz and low capacitance (C_c = 1.5 pF, C_e = 11 pF) for stable high-frequency small-signal performance.

Its thermal design relies on FR4 PCB mounting with R_th(j-a) = 250 K/W, and electrical behavior includes temperature-dependent V_BE (−2 mV/K) and V_BEsat (−1.7 mV/K), supporting predictable biasing in ambient ranges from −65 °C to +150 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - maximum safe collector-emitter voltage under open-base condition, defining rail limits in amplifier and switch designs
I_C (DC)	100 mA - continuous collector current rating, sets upper bound for load-driving capability in linear or switching operation
h_FE	420–800 at V_CE = 5 V, I_C = 2 mA - wide DC gain range enabling flexible bias network design without gain-critical layout
V_CEsat	≤250 mV at I_C = 10 mA, I_B = 0.5 mA - low saturation voltage minimizes power loss and heating in switching applications
F (Noise Figure)	≤4 dB at V_CE = 5 V, I_C = 200 μA, RS = 2 kΩ, 10 Hz–15.7 kHz - confirms suitability for low-noise preamplifier input stages
R_th(j-a)	250 K/W - thermal resistance value used to calculate junction temperature rise above ambient on standard FR4 board

Pinout & Package

BC549C,112 is housed in a plastic single-ended leaded (through-hole) TO-92 package (SOT54 / SC-43A), with 3 leads and standardized 2.54 mm lead pitch.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit node; connected to ground or low-impedance return path in common-emitter configurations
2	Base	Control terminal; requires current-limited drive (e.g., via base resistor) to bias transistor into active or saturation region
3	Collector	Current entry node; typically tied to positive supply through load in amplifier or switch topologies

Key Features

Feature	Design Value
Low noise performance	4 dB noise figure enables use in sensitive audio front-end stages without added signal degradation
High DC current gain	h_FE up to 800 supports low-base-drive designs, reducing loading on preceding circuitry
Low saturation voltage	V_CEsat ≤ 250 mV at moderate current ensures minimal conduction loss in switching applications
Stable high-frequency response	f_T = 100 MHz allows reliable operation beyond audio band into low-RF signal conditioning

Applications

Audio Preamplifier Input Stage	Signal-Level Switching Circuit
Use Scenario: Amplifying weak microphone or phono signals before further processing in consumer audio equipment. IC Role / Device Role / Timing Role: NPN small-signal amplifier operating in common-emitter configuration with emitter degeneration. Use Value: 4 dB noise figure and h_FE ≥ 420 ensure high signal fidelity and sufficient gain without external feedback complexity.	Use Scenario: Controlling LED indicators or relay coils using microcontroller GPIO outputs. IC Role / Device Role / Timing Role: Low-power saturated switch interfacing digital logic to higher-current loads. Use Value: V_CEsat ≤ 250 mV at I_C = 10 mA minimizes power dissipation and heat generation during sustained ON state.
DC Bias Reference Generator	Linear Voltage Regulator Pass Element
Use Scenario: Providing stable current reference in analog sensor signal conditioning circuits. IC Role / Device Role / Timing Role: Constant-current source configured with base bias and emitter resistor. Use Value: Tight h_FE distribution and low I_CBO (≤15 nA) support stable current output over temperature and time.	Use Scenario: Acting as series pass element in low-dropout linear regulators for portable devices. IC Role / Device Role / Timing Role: Adjustable current sink regulating output voltage via feedback-controlled base drive. Use Value: 30 V V_CEO and 500 mW power rating allow safe operation with input-to-output differentials up to 25 V at modest load currents.

Audio Preamplifier Input Stage

Signal-Level Switching Circuit

Use Scenario: Amplifying weak microphone or phono signals before further processing in consumer audio equipment.

IC Role / Device Role / Timing Role: NPN small-signal amplifier operating in common-emitter configuration with emitter degeneration.

Use Value: 4 dB noise figure and h_FE ≥ 420 ensure high signal fidelity and sufficient gain without external feedback complexity.

Use Scenario: Controlling LED indicators or relay coils using microcontroller GPIO outputs.

IC Role / Device Role / Timing Role: Low-power saturated switch interfacing digital logic to higher-current loads.

Use Value: V_CEsat ≤ 250 mV at I_C = 10 mA minimizes power dissipation and heat generation during sustained ON state.

DC Bias Reference Generator

Linear Voltage Regulator Pass Element

Use Scenario: Providing stable current reference in analog sensor signal conditioning circuits.

IC Role / Device Role / Timing Role: Constant-current source configured with base bias and emitter resistor.

Use Value: Tight h_FE distribution and low I_CBO (≤15 nA) support stable current output over temperature and time.

Use Scenario: Acting as series pass element in low-dropout linear regulators for portable devices.

IC Role / Device Role / Timing Role: Adjustable current sink regulating output voltage via feedback-controlled base drive.

Use Value: 30 V V_CEO and 500 mW power rating allow safe operation with input-to-output differentials up to 25 V at modest load currents.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC547C	V_CEO = 45 V (vs. 30 V), h_FE = 420–800 same range, identical TO-92 package	Higher breakdown voltage suits wider supply rails; otherwise functionally interchangeable in low-noise audio and switching roles	Select BC547C when system V_CC exceeds 30 V but noise and gain requirements match BC549C,112
2N3904	V_CEO = 40 V, h_FE = 100–300 (lower gain), f_T = 300 MHz (higher), same TO-92	Lower gain requires larger base drive; higher f_T supports faster switching but noise figure not specified per datasheet	Choose 2N3904 where speed outweighs gain/noise needs, e.g., digital logic interface rather than audio amplification

Compared with BC549C,112, BC547C offers higher voltage tolerance without sacrificing gain or noise performance, while 2N3904 trades gain and noise assurance for greater switching speed-making BC549C,112 optimal for precision low-noise analog stages where both gain stability and noise floor matter.

Availability

BC549C,112 is available at Aetrix Electronics and suitable for audio preamplifiers, GPIO-driven switching circuits, DC bias references, and linear regulator pass elements requiring stable component supply and long-term obsolescence management.

Supply support for BC549C,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, delivering high-performance analog, logic, and RF solutions for automotive, industrial, and consumer markets.

The BC549C,112 belongs to NXP's legacy general-purpose transistor product line, engineered specifically for cost-sensitive, high-reliability linear and switching applications in audio, instrumentation, and control systems.

FAQ

What is the maximum collector-emitter voltage rating for BC549C,112?

The BC549C,112 has a maximum collector-emitter voltage (V_CEO) rating of 30 V under open-base conditions. This limit defines the highest DC or peak AC voltage that can be safely applied between collector and emitter without risking avalanche breakdown. Exceeding this value may cause irreversible damage. The BC549C,112 must be operated within this constraint in all circuit configurations, including switching and linear amplifier designs.

Does BC549C,112 have a specified noise figure, and under what conditions?

Yes, BC549C,112 has a maximum noise figure of 4 dB, measured at V_CE = 5 V, I_C = 200 μA, source resistance R_S = 2 kΩ, and frequency bandwidth from 10 Hz to 15.7 kHz. This specification confirms its suitability for low-noise audio preamplifier input stages. The BC549C,112 maintains this noise performance across its qualified operating temperature range and is validated per NXP's production data sheet revision dated 2004 Oct 11.

What is the DC current gain (h_FE) range for BC549C,112, and at what test conditions?

The BC549C,112 exhibits a DC current gain (h_FE) range of 420 to 800 when tested at V_CE = 5 V and I_C = 2 mA. At I_C = 10 μA, h_FE starts at minimum 270. This gain spread is inherent to silicon process variation and is fully characterized in the official NXP datasheet. Designers should account for this range when sizing base resistors or verifying bias stability in circuits using BC549C,112.

Is BC549C,112 compatible with standard TO-92 sockets and PCB footprints?

Yes, BC549C,112 uses the industry-standard TO-92 outline (SOT54 / SC-43A), with 2.54 mm lead spacing and defined mechanical dimensions per the NXP package drawing. It fits standard TO-92 sockets and matches common PCB footprints for through-hole mounting. The BC549C,112 pinout (Emitter–Base–Collector on leads 1–2–3) is consistent with JEDEC TO-92 conventions, ensuring mechanical and layout compatibility across legacy and new designs.

What is the thermal resistance from junction to ambient for BC549C,112, and how is it measured?

The thermal resistance from junction to ambient (R_th(j-a)) for BC549C,112 is 250 K/W, measured with the device mounted on a standard FR4 printed-circuit board per IEC 60134 guidelines. This value assumes natural convection cooling and no heatsink. It is used to calculate junction temperature rise (ΔT_j = P_tot × R_th(j-a)) under actual power dissipation. The BC549C,112 must remain below 150 °C junction temperature to ensure reliability and parametric compliance.

BC549C,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:: NPN

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 600mV @ 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

BC549C,112 FAQ

1.How can I place an order for BC549C,112 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC549C,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 BC549C,112 reliable?

The price and inventory of BC549C,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC549C,112 is usually 5 days.

3.What payment methods are accepted for BC549C,112?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC549C,112 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC549C,112?

BC549C,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC549C,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 BC549C,112?

For technical support, including BC549C,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC549C,112 requirements.

6.How does Aetrix verify that BC549C,112 is sourced from the original manufacturer or authorized distributors?

All BC549C,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 BC549C,112 meets industry standards.

7.What is the process for return or replacement of BC549C,112?

All BC549C,112 units undergo pre-shipment inspection (PSI). If there is an issue with BC549C,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 BC549C,112 part is unused and in its original packaging.

Return procedure for BC549C,112:

1.Submit a request within 90 days.

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

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