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

onsemi BC547AZL1

Name: BC547AZL1
Brand: onsemi
SKU: BC547AZL1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC547AZL1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC547AZL1.pdf

Description:: TRANS NPN 45V 0.1A TO92

Quantity:: RFQ Add To RFQ list

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Inventory:5,450

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Product details

Overview

BC547AZL1 from ON Semiconductor is an NPN silicon general-purpose amplifier transistor in TO-92 package, rated for V_CEO = 45 V, I_C = 100 mA, and h_FE = 110–220 (at I_C = 2 mA), commonly used in low-power linear amplification and switching circuits in consumer electronics and industrial control interfaces.

For engineers reviewing the BC547AZL1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical ratings, thermal behavior, small-signal gain-bandwidth performance, saturation voltage characteristics, and real-world substitution guidance - all specific to the BC547A variant in ZL1 ammo box packaging.

Technical Context

The BC547AZL1 operates as a discrete bipolar junction transistor with fixed NPN polarity and base-emitter junction forward biasing enabling current-controlled amplification. Its DC current gain (h_FE) is specified at two test conditions: 110–220 at I_C = 2.0 mA/V_CE = 5.0 V and 110–180 at I_C = 10 mA/V_CE = 5.0 V, supporting predictable biasing in Class-A amplifiers and saturated-switch configurations.

Small-signal parameters include f_T = 150–300 MHz (depending on I_C), C_obo = 4.5 pF at V_CB = 10 V, and NF = 2.0 dB at I_C = 0.2 mA, confirming suitability for audio-frequency amplification and low-noise preamplifier stages where bandwidth and noise floor are design-critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum collector-emitter voltage before breakdown; defines safe operating range in common-emitter amplifier or switch topologies.
I_C (continuous)	100 mA - Continuous collector current limit; sets upper bound for load-driving capability in relay drivers or LED interfaces.
h_FE (min–max)	110–220 - DC current gain range at I_C = 2 mA; enables stable bias point selection without excessive base drive overhead.
V_CE(sat)	0.25 V max at I_C = 10 mA/I_B = 0.5 mA - Low saturation voltage ensures minimal power loss and heat generation in switching applications.
f_T	150–300 MHz - Transition frequency confirms usable gain up to mid-VHF; supports wideband audio and RF front-end buffer use.
R_JA	200 °C/W - Junction-to-ambient thermal resistance; requires heatsinking or derating above ~25°C ambient for sustained 625 mW dissipation.

Pinout & Package

BC547AZL1 uses the standard TO-92 (Case 29, Style 17) through-hole plastic package with 3 leads, 4.45–5.20 mm height, and 2.54 mm lead pitch. Pin 1 is Collector, Pin 2 is Base, Pin 3 is Emitter - confirmed by ON Semiconductor marking diagram and mechanical drawings.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Current output terminal	Connected to load or supply rail; carries full emitter current minus base current; must withstand V_CEO = 45 V.
2 (Base)	Control input terminal	Receives bias current to regulate collector current; requires series resistor to limit I_B and prevent thermal runaway.
3 (Emitter)	Current return path	Typically grounded or connected to current-sense resistor; provides reference for V_BE = 0.55–0.77 V turn-on threshold.

Key Features

Feature	Design Value
Pb-free option available	BC547AZL1G variant meets RoHS compliance; no lead contamination risk during wave soldering or rework.
Low noise figure	NF = 2.0 dB at I_C = 0.2 mA - enables high-fidelity signal amplification in microphone preamps and sensor interfaces.
High f_T / low C_obo	300 MHz f_T with only 4.5 pF output capacitance - supports stable gain in multi-stage audio amplifiers without oscillation.
Wide temperature range	−55°C to +150°C operating junction range - suitable for automotive under-hood and industrial motor-control environments.

Applications

Audio Pre-amplifier Stage	Microcontroller GPIO Driver
Use Scenario: Amplifying weak analog signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Discrete NPN transconductance amplifier configured in common-emitter topology with emitter degeneration. Use Value: Delivers 110–220 h_FE and 2.0 dB noise figure at 0.2 mA bias, preserving SNR while minimizing component count versus op-amp solutions.	Use Scenario: Driving LEDs, relays, or small solenoids from 3.3 V or 5 V microcontroller outputs with limited sink/source current. IC Role / Device Role / Timing Role: Saturated switch with base resistor limiting I_B to ensure I_C/I_B ≥ 10 for hard saturation. Use Value: Achieves V_CE(sat) ≤ 0.25 V at I_C = 10 mA, reducing power loss and enabling reliable on/off control without level-shifting ICs.
Linear Voltage Regulator Pass Element	Industrial Sensor Signal Conditioning
Use Scenario: Acting as series pass transistor in adjustable linear regulators (e.g., LM317-based designs) requiring <100 mA output. IC Role / Device Role / Timing Role: Current-controlled variable resistor between input and output rails, biased via error amplifier feedback. Use Value: Supports continuous 100 mA load with 625 mW dissipation at 25°C ambient, and R_JA = 200 °C/W enables thermal management via PCB copper area.	Use Scenario: Converting low-level analog outputs from thermistors, RTDs, or bridge sensors into amplified, buffered voltage signals. IC Role / Device Role / Timing Role: DC-coupled common-collector (emitter-follower) buffer providing high input impedance and low output impedance. Use Value: Maintains linearity across −55°C to +150°C with stable h_FE and V_BE(on) = 0.55–0.77 V, ensuring accuracy in harsh-environment monitoring systems.

Audio Pre-amplifier Stage

Microcontroller GPIO Driver

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

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

Use Value: Delivers 110–220 h_FE and 2.0 dB noise figure at 0.2 mA bias, preserving SNR while minimizing component count versus op-amp solutions.

Use Scenario: Driving LEDs, relays, or small solenoids from 3.3 V or 5 V microcontroller outputs with limited sink/source current.

IC Role / Device Role / Timing Role: Saturated switch with base resistor limiting I_B to ensure I_C/I_B ≥ 10 for hard saturation.

Use Value: Achieves V_CE(sat) ≤ 0.25 V at I_C = 10 mA, reducing power loss and enabling reliable on/off control without level-shifting ICs.

Linear Voltage Regulator Pass Element

Industrial Sensor Signal Conditioning

Use Scenario: Acting as series pass transistor in adjustable linear regulators (e.g., LM317-based designs) requiring <100 mA output.

IC Role / Device Role / Timing Role: Current-controlled variable resistor between input and output rails, biased via error amplifier feedback.

Use Value: Supports continuous 100 mA load with 625 mW dissipation at 25°C ambient, and R_JA = 200 °C/W enables thermal management via PCB copper area.

Use Scenario: Converting low-level analog outputs from thermistors, RTDs, or bridge sensors into amplified, buffered voltage signals.

IC Role / Device Role / Timing Role: DC-coupled common-collector (emitter-follower) buffer providing high input impedance and low output impedance.

Use Value: Maintains linearity across −55°C to +150°C with stable h_FE and V_BE(on) = 0.55–0.77 V, ensuring accuracy in harsh-environment monitoring systems.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose amplifier transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC547BZL1	Higher h_FE range: 200–450 at I_C = 2 mA; same V_CEO, I_C, and package.	Preferred where higher gain reduces base drive requirements - e.g., low-current sensor interfaces.	Select BC547BZL1 when tighter h_FE tolerance and lower base current are critical; not drop-in due to gain shift affecting bias stability.
2N3904RLRPG	V_CEO = 40 V (vs. 45 V); h_FE = 100–300 at I_C = 10 mA; identical TO-92 footprint and pinout.	Widely stocked alternative with near-identical switching and amplification behavior in 5 V systems.	Choose 2N3904RLRPG for rapid prototyping or dual-sourcing where 5 V margin suffices and Pb-free compliance is required.

Compared with BC547AZL1, BC547BZL1 offers higher gain but less consistency across production lots, while 2N3904RLRPG trades 5 V of breakdown margin for broader global availability and tighter parametric binning - both require validation of bias network stability in gain-sensitive circuits.

Availability

BC547AZL1 is available at Aetrix Electronics and suitable for audio pre-amplification, microcontroller GPIO interfacing, and industrial sensor signal conditioning requiring stable component supply, consistent h_FE binning, and TO-92 through-hole assembly compatibility.

Supply support for BC547AZL1 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 (now part of onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, and discrete components for automotive, industrial, and consumer markets.

The BC547AZL1 belongs to the BC546/547/548 family of general-purpose NPN transistors designed for cost-sensitive, high-volume linear amplification and switching applications where reliability, thermal robustness, and standardized TO-92 compatibility are essential.

FAQ

What is the maximum collector-emitter voltage rating for BC547AZL1?

The BC547AZL1 has a maximum collector-emitter voltage (V_CEO) rating of 45 V DC. This value is defined under test condition I_C = 1.0 mA and I_B = 0, and represents the absolute maximum voltage the device can withstand before breakdown. Exceeding 45 V risks permanent damage, and design margins should keep operating V_CE below 36 V for long-term reliability. The BC547AZL1 datasheet explicitly lists this parameter in the Maximum Ratings table.

Is BC547AZL1 RoHS-compliant?

Yes, the BC547AZL1 is RoHS-compliant in its standard form, and the Pb-free variant BC547AZL1G is also available. ON Semiconductor's documentation confirms that "Pb−Free Packages are Available" for the BC546/547/548 family, and the ordering information table explicitly lists BC547AZL1G as a Pb-free option. Both variants meet EU Directive 2011/65/EU requirements for restricted hazardous substances.

What is the DC current gain (h_FE) range for BC547AZL1 at I_C = 2 mA?

The BC547AZL1 exhibits a DC current gain (h_FE) range of 110 to 220 when tested at I_C = 2.0 mA and V_CE = 5.0 V, per the Electrical Characteristics table. This gain bin corresponds specifically to the "A" suffix variant. It is distinct from BC547B (200–450) and BC547C (420–800), making BC547AZL1 appropriate for moderate-gain, stable-bias applications like emitter followers and low-noise preamps.

Does BC547AZL1 have the same pinout as other TO-92 NPN transistors like 2N3904?

Yes, BC547AZL1 uses the standard TO-92 Style 17 pinout: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter - matching 2N3904, PN2222A, and most general-purpose NPN transistors in TO-92. This mechanical and electrical compatibility allows direct physical replacement in existing layouts, though electrical differences (e.g., V_CEO, h_FE) must be verified for functional equivalence in each circuit.

What is the thermal resistance junction-to-ambient (R_JA) for BC547AZL1?

The thermal resistance junction-to-ambient (R_JA) for BC547AZL1 is 200 °C/W, as specified in the Thermal Characteristics section of the datasheet. This value assumes operation in still air with the device mounted on a standard FR-4 PCB using typical lead lengths. To maintain junction temperature below 150°C at full 625 mW dissipation, ambient temperature must remain below 25°C - otherwise, derating or heatsinking is required.

BC547AZL1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

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:: 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)

BC547AZL1 FAQ

1.How can I place an order for BC547AZL1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC547AZL1 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 BC547AZL1 reliable?

The price and inventory of BC547AZL1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC547AZL1 is usually 5 days.

3.What payment methods are accepted for BC547AZL1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC547AZL1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC547AZL1?

BC547AZL1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC547AZL1 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 BC547AZL1?

For technical support, including BC547AZL1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC547AZL1 requirements.

6.How does Aetrix verify that BC547AZL1 is sourced from the original manufacturer or authorized distributors?

All BC547AZL1 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 BC547AZL1 meets industry standards.

7.What is the process for return or replacement of BC547AZL1?

All BC547AZL1 units undergo pre-shipment inspection (PSI). If there is an issue with BC547AZL1, 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 BC547AZL1 part is unused and in its original packaging.

Return procedure for BC547AZL1:

1.Submit a request within 90 days.

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

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