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

onsemi BC548CBU

Name: BC548CBU
Brand: onsemi
SKU: BC548CBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC548CBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC548CBU.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC548CBU from ON Semiconductor is a general-purpose NPN epitaxial silicon transistor in TO-92 package, rated for V_CEO = 30 V, I_C = 100 mA, and P_C = 500 mW, with h_FE range 420–800 at I_C = 2 mA, used in low-voltage switching and small-signal amplification circuits.

For engineers reviewing the BC548CBU datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, TO-92 terminal mapping, noise performance (NF = 2.0–10.0 dB), saturation behavior (V_CE(sat) ≤ 250 mV @ I_C = 10 mA), and validated alternative options for discrete BJT selection.

Technical Context

This device operates as a linear amplifier or saturated switch in DC-coupled and low-frequency AC signal paths. Its h_FE classification "C" ensures high current gain stability across 2 mA to 10 mA collector bias points, while f_T = 300 MHz supports audio and sub-MHz RF preamplifier use.

Designed for robustness in ambient temperatures up to +150°C junction, it features low V_BE(on) (580–700 mV) and tight V_CE(sat) distribution-critical for predictable turn-on in relay drivers and logic-level interface stages where base drive current is constrained.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum safe collector-emitter voltage before breakdown; defines usable supply headroom in 24 V or lower switching rails.
h_FE (I_C = 2 mA)	420–800 - High DC current gain enables low-base-drive operation in amplifier stages and reduces required microcontroller GPIO sourcing.
V_CE(sat)	≤250 mV @ I_C = 10 mA, I_B = 0.5 mA - Ensures minimal power loss and thermal rise when used as a saturated switch in load control.
f_T	300 MHz - Supports stable small-signal amplification up to ~100 MHz with adequate gain margin; suitable for IF stages and oscillator buffers.
NF	2.0–10.0 dB @ 1 kHz - Low-noise capability allows use in microphone preamps and sensor signal conditioning without added op-amp stages.
C_ob	3.5–6.0 pF @ V_CB = 10 V - Limits high-frequency Miller effect; maintains bandwidth integrity in common-emitter configurations.

Pinout & Package

BC548CBU is housed in a JEDEC TO-92 3-lead plastic package with straight leads (bulk packing). Pin 1 is Collector, Pin 2 is Base, Pin 3 is Emitter-standardized orientation confirmed by Fairchild/ON Semiconductor mechanical drawings.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Main current output node	Connected to load or supply rail; must remain within 30 V and 100 mA limits to avoid thermal runaway or avalanche failure.
2 (Base)	Control input terminal	Receives forward-biased current to enable conduction; requires series resistor to limit I_B and ensure saturation under worst-case h_FE min.
3 (Emitter)	Current return path	Typically grounded or tied to emitter resistor for bias stabilization; establishes reference for V_BE and sets operating point.

Key Features

Feature	Design Value
High h_FE Class C	Guaranteed 420–800 gain enables single-transistor amplification of µA-level sensor outputs without cascaded stages.
Low V_CE(sat)	≤250 mV at I_C/I_B = 20 ensures >95% efficiency in 5 V logic-driven switches, reducing heat sink requirements.
Low-noise operation	NF = 2.0–10.0 dB at 1 kHz allows direct coupling of electret mics or piezoelectric sensors without external noise filtering.
TO-92 compatibility	Standard footprint supports hand-soldering, breadboarding, and legacy PCB designs-no retooling needed for replacement.

Applications

Audio Pre-amplifier Stage	Microcontroller GPIO Driver
Use Scenario: Amplifying weak signals from electret condenser microphones in voice-activated IoT nodes. IC Role / Device Role / Timing Role: Small-signal NPN amplifier configured in common-emitter topology with emitter degeneration. Use Value: Delivers ≥40 dB voltage gain at 1 kHz with <10 dB noise figure, eliminating need for dedicated op-amp ICs and reducing BOM count.	Use Scenario: Driving 12 V relay coils from 3.3 V MCU GPIO pins with limited sourcing capability. IC Role / Device Role / Timing Role: Saturated switch with fixed base resistor, turning relay on/off in response to digital control. Use Value: Achieves full saturation at I_B = 0.5 mA, enabling reliable coil actuation using only 1.6 mA total GPIO current per channel.
LED Current Regulator	Signal Level Shifter
Use Scenario: Providing constant-current drive for indicator LEDs in industrial HMI panels with variable supply voltage. IC Role / Device Role / Timing Role: Emitter-follower configured with sense resistor to set LED current independent of V_CC fluctuations. Use Value: Maintains ±5% LED brightness over 5–24 V input range due to stable h_FE and low V_BE drift, improving visual consistency.	Use Scenario: Translating 1.8 V logic outputs to 5 V TTL-compatible inputs in mixed-voltage embedded systems. IC Role / Device Role / Timing Role: Common-emitter level shifter with pull-up to 5 V and base driven by low-voltage source. Use Value: Provides clean 5 V swing with <10 ns propagation delay and no shoot-through risk-unlike MOSFET-based solutions requiring gate threshold matching.

Audio Pre-amplifier Stage

Microcontroller GPIO Driver

Use Scenario: Amplifying weak signals from electret condenser microphones in voice-activated IoT nodes.

IC Role / Device Role / Timing Role: Small-signal NPN amplifier configured in common-emitter topology with emitter degeneration.

Use Value: Delivers ≥40 dB voltage gain at 1 kHz with <10 dB noise figure, eliminating need for dedicated op-amp ICs and reducing BOM count.

Use Scenario: Driving 12 V relay coils from 3.3 V MCU GPIO pins with limited sourcing capability.

IC Role / Device Role / Timing Role: Saturated switch with fixed base resistor, turning relay on/off in response to digital control.

Use Value: Achieves full saturation at I_B = 0.5 mA, enabling reliable coil actuation using only 1.6 mA total GPIO current per channel.

LED Current Regulator

Signal Level Shifter

Use Scenario: Providing constant-current drive for indicator LEDs in industrial HMI panels with variable supply voltage.

IC Role / Device Role / Timing Role: Emitter-follower configured with sense resistor to set LED current independent of V_CC fluctuations.

Use Value: Maintains ±5% LED brightness over 5–24 V input range due to stable h_FE and low V_BE drift, improving visual consistency.

Use Scenario: Translating 1.8 V logic outputs to 5 V TTL-compatible inputs in mixed-voltage embedded systems.

IC Role / Device Role / Timing Role: Common-emitter level shifter with pull-up to 5 V and base driven by low-voltage source.

Use Value: Provides clean 5 V swing with <10 ns propagation delay and no shoot-through risk-unlike MOSFET-based solutions requiring gate threshold matching.

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. 30 V); same h_FE range and TO-92 package	Preferred where higher supply voltage margin is required, e.g., 36 V automotive accessory circuits	Select BC547CBU if design requires >30 V collector swing; otherwise BC548CBU offers tighter h_FE binning at lower cost.
2N3904TA	Lower h_FE (100–300), higher V_CEO = 40 V, identical TO-92 footprint	Better suited for fast-switching digital logic interfaces where gain linearity is less critical than speed	Choose 2N3904TA for clocked switching above 100 kHz; BC548CBU remains optimal for analog gain and low-noise biasing.

Compared with BC547CBU and 2N3904TA, BC548CBU provides the highest guaranteed h_FE among TO-92 NPNs in its voltage class, making it ideal for low-base-drive amplifier and precision current mirror applications where gain predictability directly impacts accuracy.

Availability

BC548CBU is available at Aetrix Electronics and suitable for audio pre-amplifiers, microcontroller GPIO drivers, LED current regulators, and signal level shifters requiring stable component supply and long-term manufacturability.

Supply support for BC548CBU 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 manufacturer specializing in energy-efficient power management, analog, and discrete components for automotive, industrial, and consumer markets.

BC548CBU belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line-designed for cost-sensitive, high-reliability discrete signal conditioning and switching in mass-produced electronics.

FAQ

What is the maximum collector-emitter voltage rating for BC548CBU?

The BC548CBU has a maximum collector-emitter voltage (V_CEO) rating of 30 V at T_A = 25°C. This value is absolute-exceeding it risks avalanche breakdown or permanent damage. Derating is required above 25°C ambient; consult the Absolute Maximum Ratings table in the official BC548CBU datasheet for junction temperature derating curves.

Does BC548CBU have a specified noise figure, and under what conditions?

Yes, BC548CBU has a noise figure (NF) of 2.0–10.0 dB, measured at V_CE = 5 V, I_C = 200 µA, f = 1 kHz, and R_G = 2 kΩ. This specification applies specifically to the BC546–BC548 variants; BC549/BC550 offer lower NF but differ in V_CEO and h_FE ranges.

What is the pin configuration for BC548CBU in the TO-92 package?

BC548CBU uses standard TO-92 pinout: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter, with leads viewed from the flat side of the package and leads pointing downward. This matches JEDEC TO-92 mechanical specification and is consistent across all BC546–BC550 variants.

How does the h_FE classification "C" affect BC548CBU performance in circuit design?

The "C" suffix in BC548CBU denotes h_FE = 420–800 at I_C = 2 mA and V_CE = 5 V. This high-gain bin enables predictable biasing with minimal base current, reduces sensitivity to h_FE variation across units, and supports single-stage amplification where gain >400 is required-such as in sensor front-ends.

Can BC548CBU be used as a direct replacement for BC548B or BC548A in existing designs?

Yes, BC548CBU is functionally compatible with BC548B and BC548A in most applications because all share identical package, pinout, and absolute maximum ratings. The key difference is h_FE: BC548CBU guarantees 420–800 vs. 200–450 for "B" and 110–220 for "A". Verify circuit stability under minimum h_FE if replacing lower-gain variants.

BC548CBU 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):: 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:: 300MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC548CBU FAQ

1.How can I place an order for BC548CBU through Aetrix?

Please submit a Request for Quotation (RFQ) for BC548CBU 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 BC548CBU reliable?

The price and inventory of BC548CBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC548CBU is usually 5 days.

3.What payment methods are accepted for BC548CBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC548CBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC548CBU?

BC548CBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC548CBU 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 BC548CBU?

For technical support, including BC548CBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC548CBU requirements.

6.How does Aetrix verify that BC548CBU is sourced from the original manufacturer or authorized distributors?

All BC548CBU 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 BC548CBU meets industry standards.

7.What is the process for return or replacement of BC548CBU?

All BC548CBU units undergo pre-shipment inspection (PSI). If there is an issue with BC548CBU, 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 BC548CBU part is unused and in its original packaging.

Return procedure for BC548CBU:

1.Submit a request within 90 days.

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

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