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

onsemi BC547ABU

Name: BC547ABU
Brand: onsemi
SKU: BC547ABU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC547ABU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC547ABU.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC547ABU from ON Semiconductor is an NPN epitaxial silicon transistor designed for general-purpose switching and low-noise amplification in discrete analog circuits. It delivers V_CEO = 45 V, h_FE = 110–220 (Class A), I_C = 100 mA DC, and f_T = 300 MHz, commonly deployed in audio preamplifiers, signal conditioning stages, and low-power logic interface circuits.

For engineers reviewing the BC547ABU datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92 package compatibility, Class A h_FE range, V_CEO/V_CBO ratings, saturation voltage at defined drive conditions, and noise figure performance in small-signal amplifier roles.

Technical Context

This device operates as a single NPN bipolar junction transistor with epitaxial base construction, optimized for linear amplification and saturated switching. Its design supports DC biasing at V_CE = 5 V with collector currents from 2 mA to 100 mA, and it exhibits stable h_FE across that range per Class A specification.

The BC547ABU shares core electrical characteristics-including V_CEO, I_C, P_C, and thermal limits-with the BC546/BC548/BC549/BC550 family but is distinguished by its 45 V V_CEO, 50 V V_CBO, and 6 V V_EBO, making it suitable for medium-voltage analog signal paths where higher breakdown than BC548/BC549 is required but lower noise than BC549/BC550 is not critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage before avalanche breakdown; defines upper rail limit in amplifier or switch designs.
h_FE (Class A)	110–220 - DC current gain range at V_CE = 5 V, I_C = 2 mA; determines base drive requirements for predictable saturation or linear operation.
I_C (DC)	100 mA - Continuous collector current rating; sets maximum load-handling capability in switching applications.
f_T	300 MHz - Current gain-bandwidth product at V_CE = 5 V, I_C = 10 mA; indicates usable frequency limit for small-signal amplification.
V_CE(sat)	90–250 mV at I_C = 10 mA / I_B = 0.5 mA - Low saturation voltage enables efficient on-state power dissipation in switching circuits.
NF	2.0–10.0 dB at V_CE = 5 V, I_C = 200 μA, f = 1 kHz - Noise figure suitable for line-level audio and sensor signal amplification, though higher than BC549/BC550 variants.

Pinout & Package

BC547ABU is housed in a JEDEC-standard TO-92 3-lead plastic package with straight leads (bulk packing). The case outline conforms to Figure 7 in the original Fairchild datasheet Rev. 1.1.1.

Pin/Terminal	Circuit Role	Design Meaning
1 (Top View, Flat Side Facing Up)	Collector	Main current output terminal; connects to load or supply rail in common-emitter configurations.
2	Base	Control terminal; requires current-limited drive to bias transistor into active or saturated region.
3	Emitter	Current return path; typically grounded or connected to emitter resistor for bias stability.

Key Features

Feature	Design Value
Switching & Amplifier Dual Use	Validated by V_CE(sat) ≤ 250 mV and f_T = 300 MHz - supports both digital logic interfacing and mid-band analog gain stages without redesign.
Class A h_FE Bin (110–220)	Guaranteed minimum/maximum DC gain spread - simplifies bias network design for production consistency in amplifier feedback loops.
TO-92 Package Compatibility	Standardized footprint and lead spacing - enables drop-in replacement in legacy through-hole PCBs and hand-soldered prototyping.
Low V_EBO = 6 V	Enables safe base-emitter reverse bias up to 6 V - accommodates negative-going transients in AC-coupled input stages without junction damage.

Applications

Audio Preamp Stage	Microcontroller GPIO Interface
Use Scenario: Amplifying weak microphone or piezoelectric sensor signals prior to ADC sampling in portable audio devices. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with emitter degeneration. Use Value: Delivers sufficient gain (h_FE ≥ 110) and bandwidth (f_T = 300 MHz) for 20 Hz–20 kHz fidelity while maintaining low distortion at V_CE = 5 V bias.	Use Scenario: Level-shifting and current boosting between 3.3 V microcontroller outputs and 5 V relay or LED driver inputs. IC Role / Device Role / Timing Role: Saturated NPN switch controlling external loads via base-current-driven on/off states. Use Value: Achieves V_CE(sat) ≤ 250 mV at I_C/I_B = 20, minimizing power loss and heat rise in low-duty-cycle control applications.
Linear Voltage Regulator Pass Element	Discrete Oscillator Core
Use Scenario: Acting as series pass transistor in adjustable 3-terminal linear regulators for lab bench supplies or embedded power rails. IC Role / Device Role / Timing Role: Medium-current, medium-voltage active pass element dissipating up to 500 mW. Use Value: Rated P_C = 500 mW and T_J = 150 °C allow reliable operation under continuous 100 mA load with proper heatsinking or ambient derating.	Use Scenario: Active device in Colpitts or Hartley oscillator topologies generating stable RF carriers below 100 MHz. IC Role / Device Role / Timing Role: Gain element sustaining oscillation via phase-shifted feedback network. Use Value: f_T = 300 MHz provides adequate gain margin for fundamental-mode operation up to ~80 MHz with stable h_FE and low Cob (3.5–6.0 pF).

Audio Preamp Stage

Microcontroller GPIO Interface

Use Scenario: Amplifying weak microphone or piezoelectric sensor signals prior to ADC sampling in portable audio devices.

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

Use Value: Delivers sufficient gain (h_FE ≥ 110) and bandwidth (f_T = 300 MHz) for 20 Hz–20 kHz fidelity while maintaining low distortion at V_CE = 5 V bias.

Use Scenario: Level-shifting and current boosting between 3.3 V microcontroller outputs and 5 V relay or LED driver inputs.

IC Role / Device Role / Timing Role: Saturated NPN switch controlling external loads via base-current-driven on/off states.

Use Value: Achieves V_CE(sat) ≤ 250 mV at I_C/I_B = 20, minimizing power loss and heat rise in low-duty-cycle control applications.

Linear Voltage Regulator Pass Element

Discrete Oscillator Core

Use Scenario: Acting as series pass transistor in adjustable 3-terminal linear regulators for lab bench supplies or embedded power rails.

IC Role / Device Role / Timing Role: Medium-current, medium-voltage active pass element dissipating up to 500 mW.

Use Value: Rated P_C = 500 mW and T_J = 150 °C allow reliable operation under continuous 100 mA load with proper heatsinking or ambient derating.

Use Scenario: Active device in Colpitts or Hartley oscillator topologies generating stable RF carriers below 100 MHz.

IC Role / Device Role / Timing Role: Gain element sustaining oscillation via phase-shifted feedback network.

Use Value: f_T = 300 MHz provides adequate gain margin for fundamental-mode operation up to ~80 MHz with stable h_FE and low Cob (3.5–6.0 pF).

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
BC547BTA	Same die, TO-92 ammo pack; h_FE = 200–450 (Class B); identical V_CEO, V_CBO, f_T, and saturation specs.	Higher h_FE reduces required base drive in high-gain amplifier stages but increases sensitivity to thermal drift.	Select BC547BTA when tighter gain control or reduced base current is needed; BC547ABU preferred for predictable, moderate-gain bias networks.
2N3904	V_CEO = 40 V (5 V lower), h_FE = 100–300 (broader bin), P_C = 625 mW; otherwise matches pinout and general specs.	Slightly lower breakdown margin and wider h_FE spread may require recalibration of bias resistors in precision analog designs.	Choose 2N3904 only if higher power dissipation (625 mW) is critical; BC547ABU offers better V_CEO headroom and tighter h_FE control for fixed-bias circuits.

Compared with BC547BTA and 2N3904, the BC547ABU provides the narrowest h_FE range (110–220) and highest V_CEO (45 V) among these three, making it optimal for stable, medium-voltage amplifier biasing where predictable DC operating points are essential.

Availability

BC547ABU is available at Aetrix Electronics and suitable for audio signal conditioning, microcontroller interface circuits, linear regulator pass elements, and discrete oscillator designs requiring stable component supply and long-term obsolescence management.

Supply support for BC547ABU 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 power management, analog, sensors, and discrete components for automotive, industrial, and consumer applications.

The BC547ABU belongs to ON Semiconductor's legacy general-purpose transistor product line-originally developed by Fairchild-which targets cost-sensitive, high-reliability discrete circuit functions in analog signal chains and digital interface layers.

FAQ

What is the maximum collector-emitter voltage rating for BC547ABU?

The BC547ABU has a guaranteed V_CEO (collector-emitter voltage) rating of 45 V at T_A = 25 °C. This rating defines the absolute maximum DC voltage that can be applied between collector and emitter with the base open. Exceeding this value risks avalanche breakdown and permanent device damage. Derating is required above 25 °C per the datasheet's thermal curves.

Is BC547ABU pin-compatible with other TO-92 NPN transistors like 2N2222 or PN2222?

Yes, BC547ABU uses the standard TO-92 package with Collector-Base-Emitter pinout (1-2-3, flat side up), matching 2N2222 and PN2222. However, electrical parameters differ significantly: BC547ABU has lower V_CEO (45 V vs. 40 V for 2N2222) but higher f_T (300 MHz vs. 250 MHz), and its h_FE bin (110–220) is narrower. Direct substitution requires validation of gain, speed, and voltage margins in the target circuit.

What does the 'A' suffix in BC547ABU indicate?

The 'A' in BC547ABU denotes the h_FE classification bin: DC current gain between 110 and 220 at V_CE = 5 V and I_C = 2 mA. This distinguishes it from BC547B (200–450) and BC547C (420–800). The 'BU' suffix specifies bulk packaging in TO-92 straight-lead configuration, per Fairchild/ON Semiconductor ordering nomenclature.

Can BC547ABU be used in low-noise amplifier applications?

BC547ABU has a noise figure of 2.0–10.0 dB at 1 kHz, which is acceptable for non-critical audio preamps but higher than low-noise variants like BC549B (1.4–4.0 dB) or BC550C (1.4–3.0 dB). For applications demanding sub-2 dB NF-such as phono stage inputs or precision sensor amplifiers-the BC547ABU is not recommended; BC549 or BC550 should be selected instead.

What is the thermal resistance junction-to-ambient (R_θJA) for BC547ABU in TO-92 package?

The BC547ABU datasheet does not specify R_θJA as a standalone parameter, but its maximum junction temperature (T_J) is 150 °C and maximum power dissipation (P_C) is 500 mW at T_A = 25 °C. Using P_C = (T_J − T_A) / R_θJA, the implied R_θJA is approximately 250 °C/W under still-air conditions on a standard FR-4 PCB with minimal copper area-consistent with typical TO-92 thermal performance.

BC547ABU 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):: 45 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 110 @ 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

BC547ABU FAQ

1.How can I place an order for BC547ABU through Aetrix?

Please submit a Request for Quotation (RFQ) for BC547ABU 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 BC547ABU reliable?

The price and inventory of BC547ABU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC547ABU is usually 5 days.

3.What payment methods are accepted for BC547ABU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC547ABU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC547ABU?

BC547ABU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC547ABU 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 BC547ABU?

For technical support, including BC547ABU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC547ABU requirements.

6.How does Aetrix verify that BC547ABU is sourced from the original manufacturer or authorized distributors?

All BC547ABU 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 BC547ABU meets industry standards.

7.What is the process for return or replacement of BC547ABU?

All BC547ABU units undergo pre-shipment inspection (PSI). If there is an issue with BC547ABU, 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 BC547ABU part is unused and in its original packaging.

Return procedure for BC547ABU:

1.Submit a request within 90 days.

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

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