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

onsemi BC547ARLG

Name: BC547ARLG
Brand: onsemi
SKU: BC547ARLG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC547ARLG

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body, Formed Leads

Datasheet:: BC547ARLG.pdf

Description:: TRANS NPN 45V 0.1A TO92

Quantity:: RFQ Add To RFQ list

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Inventory:7,152

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Product details

Overview

BC547ARLG from onsemi is an NPN silicon general-purpose amplifier transistor in TO-92 package, rated for 45 V_CEO, 100 mA continuous collector current, and 625 mW power dissipation at 25°C ambient. It delivers DC current gain (h_FE) of 110–220 at I_C = 10 mA, V_CE = 5 V, and supports small-signal amplification up to 300 MHz f_T. It is widely used in low-power linear amplifiers, switching circuits, and sensor interface stages.

For engineers reviewing the BC547ARLG datasheet, pinout, applications, or equivalent options, key selection criteria include its V_CEO rating, h_FE bin (A-grade), thermal resistance (R_JA = 200°C/W), Pb-free TO-92 packaging, and compatibility with low-voltage bias networks in discrete analog front-ends.

Technical Context

The BC547ARLG operates as a standard bipolar junction transistor with fixed-emitter configuration, requiring external base biasing for active-region amplification or saturation-mode switching. Its h_FE range (110–220) and low V_CE(sat) (0.25 V max at I_C = 10 mA, I_B = 0.5 mA) support stable Class-A amplification and reliable digital logic-level interfacing.

Thermal design relies on its R_JA = 200°C/W and R_JC = 83.3°C/W ratings, enabling operation from −55°C to +150°C junction temperature. The device exhibits C_obo = 1.7–4.5 pF and f_T = 300 MHz, confirming suitability for audio-frequency and low-MHz RF preamplifier stages without parasitic oscillation risk.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage before breakdown; defines rail headroom in amplifier and switch designs.
I_C (continuous)	100 mA - Absolute maximum DC collector current; sets upper limit for load-driving capability in switching applications.
P_D @ T_A = 25°C	625 mW - Power dissipation limit at room ambient; derates 5 mW/°C above 25°C for thermal safety margin.
h_FE @ I_C = 10 mA	110–220 - A-grade DC current gain spread; enables predictable bias point setting in emitter-follower and common-emitter stages.
f_T	300 MHz - Current-gain bandwidth product; confirms usability in wideband audio and sub-300 MHz RF signal conditioning.
V_CE(sat)	0.25 V max @ I_C/I_B = 10 - Low saturation voltage minimizes conduction loss in digital switching and relay drivers.
R_JA	200°C/W - Junction-to-ambient thermal resistance; determines required PCB copper area and airflow for thermal management.

Pinout & Package

BC547ARLG uses the TO-92 (Case 29, Style 17) plastic package with bent leads and Pb-free finish. Dimensions conform to JEDEC TO-226 outline: 4.45–5.20 mm height, 4.32–5.33 mm width, 3.18–4.19 mm thickness, and 2.54 mm lead pitch.

Pin/Terminal	Circuit Role	Design Meaning
1 - Collector	Main output current terminal	Connected to load or supply rail; carries full collector current and dissipates most heat in active/saturation modes.
2 - Base	Control input terminal	Receives bias current to regulate collector-emitter conduction; requires current-limiting resistor in most configurations.
3 - Emitter	Reference current terminal	Typically grounded or tied to bias network; establishes emitter voltage reference for gain stability and thermal compensation.

Key Features

Feature	Design Value
Pb-free TO-92 package	Complies with RoHS Directive 2011/65/EU; eliminates lead contamination risk during reflow soldering and end-of-life recycling.
100 mA I_C rating	Supports direct driving of LEDs, small relays, and logic-level MOSFET gates without external buffer stages.
V_CEO = 45 V	Enables use in 24 V industrial control inputs, automotive accessory circuits, and multi-cell battery-powered systems.
h_FE = 110–220 (A-grade)	Reduces variation in DC operating points across production batches, simplifying bias network design and calibration.
f_T = 300 MHz	Permits stable small-signal amplification up to 100 kHz with >60 dB gain margin, suitable for microphone preamps and sensor signal chains.

Applications

Audio Pre-amplifier Stage	Microcontroller GPIO Driver
Use Scenario: Amplifying low-level signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: NPN common-emitter amplifier providing 20–40 dB voltage gain with minimal distortion. Use Value: Low noise figure (2.0 dB) and high h_FE ensure clean signal integrity and consistent gain across temperature.	Use Scenario: Level-shifting and current boosting for 3.3 V microcontroller outputs driving 5 V peripherals or indicator LEDs. IC Role / Device Role / Timing Role: Digital switch operating in saturation mode to sink up to 100 mA load current. Use Value: V_CE(sat) ≤ 0.25 V ensures <100 mW power loss at full load, eliminating need for heatsinking.
Industrial Sensor Interface	Power Supply Enable Control
Use Scenario: Conditioning output from thermistor-based temperature sensing circuits in HVAC controllers. IC Role / Device Role / Timing Role: Emitter-follower buffer isolating high-impedance sensor network from downstream ADC input. Use Value: High input impedance and low output impedance maintain signal fidelity while rejecting PCB noise coupling.	Use Scenario: Enabling/disabling auxiliary 12 V rails in programmable power supplies via microcontroller command. IC Role / Device Role / Timing Role: High-side or low-side switch controlling gate/base of power MOSFET or regulator enable pin. Use Value: 45 V V_CEO rating safely handles transient spikes on 12 V/24 V supply lines without clamping diodes.

Audio Pre-amplifier Stage

Microcontroller GPIO Driver

Use Scenario: Amplifying low-level signals from electret microphones or piezoelectric sensors before ADC sampling.

IC Role / Device Role / Timing Role: NPN common-emitter amplifier providing 20–40 dB voltage gain with minimal distortion.

Use Value: Low noise figure (2.0 dB) and high h_FE ensure clean signal integrity and consistent gain across temperature.

Use Scenario: Level-shifting and current boosting for 3.3 V microcontroller outputs driving 5 V peripherals or indicator LEDs.

IC Role / Device Role / Timing Role: Digital switch operating in saturation mode to sink up to 100 mA load current.

Use Value: V_CE(sat) ≤ 0.25 V ensures <100 mW power loss at full load, eliminating need for heatsinking.

Industrial Sensor Interface

Power Supply Enable Control

Use Scenario: Conditioning output from thermistor-based temperature sensing circuits in HVAC controllers.

IC Role / Device Role / Timing Role: Emitter-follower buffer isolating high-impedance sensor network from downstream ADC input.

Use Value: High input impedance and low output impedance maintain signal fidelity while rejecting PCB noise coupling.

Use Scenario: Enabling/disabling auxiliary 12 V rails in programmable power supplies via microcontroller command.

IC Role / Device Role / Timing Role: High-side or low-side switch controlling gate/base of power MOSFET or regulator enable pin.

Use Value: 45 V V_CEO rating safely handles transient spikes on 12 V/24 V supply lines without clamping diodes.

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
BC547BRL1G	Same TO-92 Pb-free package; h_FE bin 200–450 (B-grade) instead of 110–220 (A-grade).	Higher gain variability increases bias sensitivity; less suitable for precision DC-coupled amplifiers.	Select BC547BRL1G only when higher h_FE is needed and circuit tolerates wider gain spread.
MMBT3904LT1G	SOT-23 surface-mount package; identical V_CEO = 40 V, I_C = 200 mA, but f_T = 300 MHz and h_FE = 100–300.	Smaller footprint and higher current rating, but requires re-layout and different thermal management strategy.	Choose MMBT3904LT1G for space-constrained PCBs where automated SMT assembly is preferred over through-hole.

Compared with BC547BRL1G and MMBT3904LT1G, BC547ARLG offers tighter h_FE tolerance for stable biasing in analog stages and through-hole manufacturability without rework overhead, making it optimal for prototyping and low-volume industrial controls.

Availability

BC547ARLG is available at Aetrix Electronics and suitable for audio pre-amplifiers, microcontroller GPIO drivers, industrial sensor interfaces, and power supply enable control requiring stable component supply and RoHS-compliant sourcing.

Supply support for BC547ARLG 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC547ARLG belongs to onsemi's legacy general-purpose transistor family designed for cost-sensitive, high-reliability linear and switching applications in industrial controls, instrumentation, and embedded systems.

FAQ

What is the maximum collector-emitter voltage rating for BC547ARLG?

The BC547ARLG has a maximum collector-emitter voltage (V_CEO) rating of 45 VDC. This value is specified under test conditions of I_C = 1.0 mA and I_B = 0, and represents the highest voltage that can be applied between collector and emitter while keeping the transistor in the off state without risking avalanche breakdown. Exceeding this rating may cause irreversible damage to the BC547ARLG.

Is BC547ARLG RoHS-compliant and what does the 'G' suffix indicate?

Yes, BC547ARLG is RoHS-compliant. The 'G' suffix in BC547ARLG explicitly denotes a Pb-free (lead-free) construction per EU Directive 2011/65/EU, verified by onsemi's material declarations. This applies to both the die attach and lead finish, ensuring compatibility with modern reflow profiles and environmental compliance requirements for BC547ARLG in commercial and industrial products.

What is the DC current gain (h_FE) range for BC547ARLG at typical operating conditions?

The BC547ARLG is an A-grade device with a guaranteed h_FE range of 110 to 220 when tested at I_C = 10 mA and V_CE = 5.0 V. This binning provides tighter gain consistency than B- or C-grade variants, reducing the need for individual calibration in production BC547ARLG circuits such as fixed-gain sensor amplifiers or LED current regulators.

Can BC547ARLG be used in switching applications, and what is its typical V_CE(sat)?

Yes, BC547ARLG is routinely used in low-speed switching applications. Its typical V_CE(sat) is 0.09 V, with a maximum of 0.25 V at I_C = 10 mA and I_B = 0.5 mA (I_C/I_B = 10). This low saturation voltage ensures minimal power loss-under 2.5 mW at 10 mA-making BC547ARLG effective for driving indicators, relays, and logic-level translation without added heat sinking.

What package type and pin configuration does BC547ARLG use?

BC547ARLG uses the TO-92 (Case 29, Style 17) through-hole plastic package with bent leads. Pin 1 is Collector, Pin 2 is Base, and Pin 3 is Emitter-confirmed by onsemi's mechanical drawings and marking diagram. This standardized pinout ensures compatibility with legacy sockets, breadboards, and manual assembly workflows for BC547ARLG in development and repair environments.

BC547ARLG Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body, Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

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

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

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 500µA, 10mA

Current - Collector Cutoff (Max):: 15nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 110 @ 2mA, 5V

Power - Max:: 625 mW

Frequency - Transition:: 300MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

BC547ARLG FAQ

1.How can I place an order for BC547ARLG through Aetrix?

Please submit a Request for Quotation (RFQ) for BC547ARLG 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 BC547ARLG reliable?

The price and inventory of BC547ARLG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC547ARLG is usually 5 days.

3.What payment methods are accepted for BC547ARLG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC547ARLG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC547ARLG?

BC547ARLG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC547ARLG 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 BC547ARLG?

For technical support, including BC547ARLG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC547ARLG requirements.

6.How does Aetrix verify that BC547ARLG is sourced from the original manufacturer or authorized distributors?

All BC547ARLG 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 BC547ARLG meets industry standards.

7.What is the process for return or replacement of BC547ARLG?

All BC547ARLG units undergo pre-shipment inspection (PSI). If there is an issue with BC547ARLG, 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 BC547ARLG part is unused and in its original packaging.

Return procedure for BC547ARLG:

1.Submit a request within 90 days.

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

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