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

STMicroelectronics BC107B

Name: BC107B
Brand: STMicroelectronics
SKU: BC107B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC107B

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-206AA, TO-18-3 Metal Can

Datasheet:: BC107B.pdf

Description:: TRANS NPN 45V 0.1A TO-18

Quantity:: RFQ Add To RFQ list

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Inventory:2,557

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Product details

Overview

BC107B from STMicroelectronics is a silicon planar epitaxial NPN bipolar junction transistor in TO-18 metal package, designed for low-noise audio amplifier input stages and signal processing circuits. It delivers h_FE = 200–450 (IC = 2 mA, V_CE = 5 V), noise figure = 2–10 dB (IC = 0.2 mA, f = 1 kHz), V_CEO = 45 V, I_C = 100 mA, and C_CB = 4–6 pF - enabling high-fidelity preamplifier use in TV receiver front-ends.

For engineers reviewing the BC107B datasheet, BC107B pinout, BC107B application, or BC107B equivalent, key selection considerations include its verified low-noise performance at 0.2 mA bias, TO-18 thermal resistance (R_thj-case = 200 °C/W), h_FE binning consistency, and complementary pairing with BC177B for push-pull audio stages.

Technical Context

The BC107B operates as a general-purpose low-noise NPN amplifier with DC current gain binned to 200–450 and small-signal h_fe up to 300 at 1 kHz. Its 2–10 dB noise figure at 1 kHz (R_g = 2 kΩ, B = 200 Hz) and low C_CB (4–6 pF) support stable high-input-impedance amplification in audio-frequency signal chains.

It features V_CEO = 45 V and V_CBO = 50 V ratings, enabling safe operation in low-voltage analog stages up to ±22 V supply rails. The TO-18 metal case provides robust thermal conduction (R_thj-case = 200 °C/W) and EMI shielding critical for sensitive preamp nodes.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - supports rail-to-rail operation in ±15 V audio preamp supplies without breakdown risk
h_FE	200–450 @ IC = 2 mA - ensures predictable DC bias stability across production lots for fixed-bias amplifier designs
Noise Figure	2–10 dB @ IC = 0.2 mA, f = 1 kHz - enables sub-10 µV input-referred noise in microphone preamplifiers
C_CB	4–6 pF @ V_CB = 10 V - minimizes Miller effect distortion in high-gain common-emitter configurations
R_thj-case	200 °C/W - allows 300 mW dissipation at case temperature ≤25 °C, supporting continuous low-power audio stage operation
V_BE(sat)	750–950 mV @ IC = 10 mA - defines base drive requirement for reliable saturation in switching applications

Pinout & Package

TO-18 metal can package with hermetically sealed construction, 3-terminal configuration (Emitter, Base, Collector), and integrated heat slug for direct mounting to heatsinks or chassis ground.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Connected to circuit ground or emitter resistor; sets DC bias point and AC signal reference
Base (B)	Control input	Receives input signal or bias current; requires impedance-matched drive to minimize noise injection
Collector (C)	Current source output	Delivers amplified output current; connected to load resistor or next-stage input via coupling capacitor

Key Features

Feature	Design Value
Low-noise audio grade	Verified 2–10 dB noise figure at 1 kHz enables high-SNR preamplification of weak signals
Binned h_FE range	200–450 spread ensures consistent gain matching in dual-channel or differential pair designs
TO-18 metal package	Provides EMI shielding and 200 °C/W thermal resistance for stable operation in noisy environments
Complementary PNP pairing	Validated compatibility with BC177B for Class-B/AB audio output stages

Applications

TV Receiver Input Stage

Audio Preamplifier

Use Scenario: Amplifying weak RF/IF-derived audio signals prior to demodulation in analog television receivers.

IC Role / Device Role / Timing Role: Low-noise NPN transistor configured in common-emitter topology for voltage gain and impedance transformation.

Use Value: 2–10 dB noise figure preserves SNR of microvolt-level signals, preventing degradation before detection.

Use Scenario: Boosting microphone or phono cartridge output to line level in consumer audio equipment.

IC Role / Device Role / Timing Role: First-stage discrete amplifier with emitter degeneration for linear gain control and DC bias stability.

Use Value: h_FE = 200–450 enables precise bias setting across units; TO-18 shielding reduces hum pickup.

Signal Processing Filter Driver

Differential Pair Input Stage

Use Scenario: Driving active RC filter networks in analog equalizers or tone controls.

IC Role / Device Role / Timing Role: Voltage follower or gain stage buffering high-impedance filter inputs to prevent loading.

Use Value: C_CB = 4–6 pF minimizes phase shift and resonance in feedback paths up to 100 kHz.

Use Scenario: Forming matched input pairs in instrumentation amplifiers or balanced modulators.

IC Role / Device Role / Timing Role: One half of a thermally coupled NPN pair with BC107B's h_FE binning ensuring gain symmetry.

Use Value: Tight h_FE spread (200–450) and TO-18 thermal coupling reduce offset drift vs. plastic-packaged alternatives.

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise NPN amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC547B	TO-92 plastic package; h_FE = 200–450; NF = 10 dB typical; R_thj-amb = 500 °C/W	Lacks EMI shielding and thermal performance; unsuitable for high-humidity or RF-dense environments	Prefer BC107B where chassis grounding, thermal stability, or noise immunity is required
2N3904	TO-92; V_CEO = 40 V; h_FE = 100–300; C_CB = 4.5 pF; NF = 5 dB typical	Lower V_CEO limits headroom in ±18 V designs; wider h_FE tolerance increases bias variance	Select BC107B when 45 V rating and tighter h_FE binning are needed for production consistency

Compared with BC547B and 2N3904, the BC107B offers superior thermal management (200 °C/W vs. ≥500 °C/W), hermetic TO-18 EMI shielding, and narrower h_FE distribution - making it preferred for production-grade audio front-ends demanding long-term bias stability and noise integrity.

Availability

BC107B is available at Aetrix Electronics and suitable for TV receiver input stages, audio preamplifiers, signal processing filter drivers, and differential pair input stages requiring stable component supply and repeatable low-noise performance.

Supply support for BC107B 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The BC107B belongs to ST's legacy bipolar transistor product line, engineered specifically for high-reliability, low-noise analog signal conditioning in broadcast and professional audio systems.

FAQ

What is the maximum safe collector current for continuous operation?

The BC107B supports 100 mA collector current under specified conditions, but continuous operation at this level requires case temperature ≤25 °C due to its 300 mW total dissipation limit. At higher ambient temperatures, derating per the R_thj-amb = 500 °C/W curve is mandatory to avoid junction overheating.

How does BC107B differ from BC107 in terms of DC current gain?

The BC107B is the high-gain variant: its h_FE is binned 200–450 at IC = 2 mA, while the standard BC107 is binned 110–150. Both share identical absolute maximum ratings and thermal characteristics, making BC107B the preferred choice for gain-critical low-noise stages.

Can BC107B be used in switching applications?

Yes - its V_CE(sat) = 70–250 mV and h_FE > 200 support reliable saturation in low-speed switching (≤100 kHz). However, its f_T is not specified, and C_CB/C_EB values indicate it is optimized for audio frequencies, not RF or fast digital switching.

Is BC107B pin-compatible with BC177B?

No - BC107B is NPN and BC177B is PNP; they are complementary types, not pin-compatible. Their pinouts differ: BC107B has E-B-C clockwise in TO-18 view, while BC177B uses E-B-C counterclockwise. They are intended for paired use in push-pull topologies, not direct substitution.

BC107B Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-206AA, TO-18-3 Metal Can

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 600mV @ 5mA, 100mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 2mA, 5V

Power - Max:: 300 mW

Frequency - Transition:: -

Operating Temperature:: 175°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-18

BC107B FAQ

1.How can I place an order for BC107B through Aetrix?

Please submit a Request for Quotation (RFQ) for BC107B 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 BC107B reliable?

The price and inventory of BC107B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC107B is usually 5 days.

3.What payment methods are accepted for BC107B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC107B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC107B?

BC107B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC107B 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 BC107B?

For technical support, including BC107B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC107B requirements.

6.How does Aetrix verify that BC107B is sourced from the original manufacturer or authorized distributors?

All BC107B 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 BC107B meets industry standards.

7.What is the process for return or replacement of BC107B?

All BC107B units undergo pre-shipment inspection (PSI). If there is an issue with BC107B, 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 BC107B part is unused and in its original packaging.

Return procedure for BC107B:

1.Submit a request within 90 days.

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

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