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

onsemi BC546CBU

Name: BC546CBU
Brand: onsemi
SKU: BC546CBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC546CBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC546CBU.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC546CBU from ON Semiconductor is a general-purpose NPN epitaxial silicon transistor in TO-92 package, rated for 65 V V_CEO, 100 mA I_C, and 500 mW P_C, with h_FE of 420–800 at I_C = 2 mA, used in low-noise amplifier and switching stages of consumer audio preamps and sensor interface circuits.

For engineers reviewing the BC546CBU datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, TO-92 terminal mapping, real-world use cases, and two validated alternative transistors for discrete BJT design validation and sourcing continuity.

Technical Context

This device operates as a medium-voltage, low-current bipolar junction transistor optimized for linear amplification and saturated switching. Its h_FE classification (C-grade) ensures consistent DC current gain across production lots, while f_T = 300 MHz supports audio-frequency signal integrity and fast edge response in digital logic interfaces.

Designed for single-supply operation, it features V_BE(on) = 580–700 mV at I_C = 2 mA and V_CE(sat) ≤ 250 mV at I_C = 10 mA / I_B = 0.5 mA - enabling reliable biasing in Class-A amplifiers and low-loss switching in LED drivers and relay control stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	65 V - supports rail voltages up to ±32 V in dual-supply op-amp stages or 48 V industrial control inputs.
I_C (DC)	100 mA - sufficient for driving small relays, LEDs, or pre-driver stages without external heat sinking.
h_FE	420–800 at V_CE = 5 V, I_C = 2 mA - enables high-gain, low-base-current bias networks in microphone preamplifiers.
f_T	300 MHz - preserves signal fidelity through 20 kHz audio bandwidth with margin for harmonic content.
V_CE(sat)	≤250 mV at I_C = 10 mA / I_B = 0.5 mA - minimizes power loss and thermal rise in on-state switching applications.
P_C	500 mW - allows continuous operation at 100 mA with <10 °C/W ambient-to-case rise under standard PCB mounting.

Pinout & Package

BC546CBU uses the industry-standard TO-92 3-lead plastic package with straight leads (JEDEC TO-92 compliant), pin 1 = Collector, pin 2 = Base, pin 3 = Emitter - verified per Fairchild/ON Semiconductor physical dimensions documentation and ordering information tables.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Current sink node	Connected to load or supply rail; handles full output current and voltage stress during switching or amplification.
2 (Base)	Control input	Receives bias current to regulate collector-emitter conduction; requires series resistor for stable DC operating point.
3 (Emitter)	Current source node	Common reference for base bias and load return path; often tied to ground or emitter degeneration resistor.

Key Features

Feature	Design Value
High-Voltage Rating	V_CEO = 65 V enables use in 48 V telecom line cards and automotive body-control modules without derating.
Low-Noise Amplification	NF = 2.0–10.0 dB at 1 kHz supports clean signal gain in electret microphone front-ends and sensor signal conditioning.
C-Grade h_FE Bin	h_FE = 420–800 reduces component-level gain variation, simplifying production calibration in analog instrumentation.
TO-92 Compatibility	Standard footprint allows drop-in replacement in legacy designs using BC546A/B/C, BC547C, or BC548C variants.

Applications

Audio Pre-amplifier Stage	Sensor Signal Conditioning
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Discrete NPN transistor configured in common-emitter topology for voltage gain and impedance matching. Use Value: Low noise figure (2.0–10.0 dB) and stable h_FE ensure SNR > 60 dB in 20 Hz–20 kHz band without active feedback compensation.	Use Scenario: Converting low-level analog outputs from temperature or pressure transducers into robust drive levels for microcontroller inputs. IC Role / Device Role / Timing Role: Linear amplifier with emitter-degeneration bias for temperature-stable DC gain and offset control. Use Value: V_BE(on) tolerance (580–700 mV) and tight h_FE bin enable predictable gain accuracy within ±5% across 0–70°C ambient range.
LED Driver Switch	Relay Control Interface
Use Scenario: Driving indicator or status LEDs in industrial HMIs and embedded panels requiring low standby current. IC Role / Device Role / Timing Role: Saturated switch with base resistor limiting I_B to ensure forced β ≥ 10 for guaranteed turn-on. Use Value: V_CE(sat) ≤ 250 mV at I_C = 10 mA keeps LED forward voltage drop stable and power dissipation below 2.5 mW.	Use Scenario: Isolating MCU GPIO pins from inductive relay coils in home automation and PLC I/O modules. IC Role / Device Role / Timing Role: Darlington-compatible driver stage providing current gain to energize 12 V/24 V relay coils. Use Value: 65 V V_CEO withstands flyback spikes up to 60 V, eliminating need for external clamp diodes in most 24 V systems.

Audio Pre-amplifier Stage

Sensor Signal Conditioning

Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling.

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

Use Value: Low noise figure (2.0–10.0 dB) and stable h_FE ensure SNR > 60 dB in 20 Hz–20 kHz band without active feedback compensation.

Use Scenario: Converting low-level analog outputs from temperature or pressure transducers into robust drive levels for microcontroller inputs.

IC Role / Device Role / Timing Role: Linear amplifier with emitter-degeneration bias for temperature-stable DC gain and offset control.

Use Value: V_BE(on) tolerance (580–700 mV) and tight h_FE bin enable predictable gain accuracy within ±5% across 0–70°C ambient range.

LED Driver Switch

Relay Control Interface

Use Scenario: Driving indicator or status LEDs in industrial HMIs and embedded panels requiring low standby current.

IC Role / Device Role / Timing Role: Saturated switch with base resistor limiting I_B to ensure forced β ≥ 10 for guaranteed turn-on.

Use Value: V_CE(sat) ≤ 250 mV at I_C = 10 mA keeps LED forward voltage drop stable and power dissipation below 2.5 mW.

Use Scenario: Isolating MCU GPIO pins from inductive relay coils in home automation and PLC I/O modules.

IC Role / Device Role / Timing Role: Darlington-compatible driver stage providing current gain to energize 12 V/24 V relay coils.

Use Value: 65 V V_CEO withstands flyback spikes up to 60 V, eliminating need for external clamp diodes in most 24 V systems.

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
BC547CBU	V_CEO = 45 V (vs. 65 V); same h_FE bin, TO-92 package, identical pinout.	Limited to ≤36 V supply rails; unsuitable for 48 V telecom or industrial bus interfaces.	Select when system voltage is ≤30 V and cost sensitivity outweighs voltage headroom needs.
BC548CBU	V_CEO = 30 V; lower h_FE min (420 vs. same), higher Cob (6.0 pF vs. 3.5–6.0 pF typical).	Reduced high-frequency response and lower breakdown margin restrict use to sub-24 V battery-powered devices.	Prefer only for ultra-low-cost consumer electronics where voltage and RF performance are non-critical.

Compared with BC547CBU and BC548CBU, BC546CBU provides 20 V higher collector-emitter breakdown and superior noise performance - making it the preferred choice for 36–48 V analog front-ends and precision switching where reliability margins matter.

Availability

BC546CBU is available at Aetrix Electronics and suitable for audio pre-amplifier stages, sensor signal conditioning, LED driver switches, and relay control interfaces requiring stable component supply and long-term industrial availability.

Supply support for BC546CBU 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.

BC546CBU belongs to the legacy BC5xx family of general-purpose NPN transistors originally developed by Fairchild and now maintained by ON Semiconductor for broad compatibility in cost-sensitive, high-volume analog and switching circuits.

FAQ

What is the maximum collector-emitter voltage rating for BC546CBU?

The BC546CBU has a maximum collector-emitter voltage (V_CEO) rating of 65 V at T_A = 25°C. This allows safe operation in 48 V systems with margin for transient spikes. Derating is required above 25°C ambient per the datasheet's thermal curves, and absolute maximum ratings must never be exceeded to avoid permanent damage to the BC546CBU.

Does BC546CBU have a specified noise figure, and what is its typical value?

Yes, BC546CBU has a specified noise figure (NF) of 2.0–10.0 dB at V_CE = 5 V, I_C = 200 μA, f = 1 kHz, and R_G = 2 kΩ. This low-noise performance makes BC546CBU suitable for microphone preamplifiers and sensor front-ends where signal integrity is critical. The BC546CBU's NF is better than BC548/BC549 variants in the same family.

What is the h_FE range for BC546CBU, and how is it binned?

The BC546CBU is binned to the "C" h_FE classification, with a guaranteed DC current gain range of 420–800 at V_CE = 5 V and I_C = 2 mA. This tighter gain spread improves predictability in production amplifier designs versus "A" (110–220) or "B" (200–450) grades, reducing calibration overhead when using BC546CBU in gain-critical analog stages.

Can BC546CBU be used as a direct replacement for BC547CBU in an existing design?

BC546CBU shares the same TO-92 package, pinout (C-B-E), and h_FE bin as BC547CBU but offers higher V_CEO (65 V vs. 45 V). It is electrically compatible and mechanically interchangeable, making BC546CBU a functional upgrade in designs where voltage headroom is needed - though layout changes are unnecessary due to identical footprint and terminal assignment.

What is the power dissipation limit of BC546CBU, and how does thermal resistance affect its use?

The BC546CBU has a maximum collector power dissipation (P_C) of 500 mW at T_A = 25°C. Its thermal resistance (R_θJA) is approximately 200°C/W, meaning junction temperature rises ~100°C at full 500 mW dissipation. For reliable operation, BC546CBU should be operated below 300 mW in still-air environments or mounted on copper pour to reduce thermal resistance and maintain T_J < 125°C.

BC546CBU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 65 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:: 300MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC546CBU FAQ

1.How can I place an order for BC546CBU through Aetrix?

Please submit a Request for Quotation (RFQ) for BC546CBU 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 BC546CBU reliable?

The price and inventory of BC546CBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC546CBU is usually 5 days.

3.What payment methods are accepted for BC546CBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC546CBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC546CBU?

BC546CBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC546CBU 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 BC546CBU?

For technical support, including BC546CBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC546CBU requirements.

6.How does Aetrix verify that BC546CBU is sourced from the original manufacturer or authorized distributors?

All BC546CBU 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 BC546CBU meets industry standards.

7.What is the process for return or replacement of BC546CBU?

All BC546CBU units undergo pre-shipment inspection (PSI). If there is an issue with BC546CBU, 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 BC546CBU part is unused and in its original packaging.

Return procedure for BC546CBU:

1.Submit a request within 90 days.

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

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