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

onsemi BC547ATAR

Name: BC547ATAR
Brand: onsemi
SKU: BC547ATAR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC547ATAR

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC547ATAR.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:5,545

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Product details

Overview

BC547ATAR from ON Semiconductor is a general-purpose NPN epitaxial silicon transistor in TO-92 package, rated for V_CEO = 45 V, I_C = 100 mA, and P_C = 500 mW, with h_FE classification A (110–220) and f_T = 300 MHz - widely used in low-power switching and small-signal amplification circuits such as sensor interfaces and LED drivers.

For engineers reviewing the BC547ATAR datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain range, saturation voltage at defined I_C/I_B, noise figure (2.0–10.0 dB), V_CEO rating, and TO-92 mechanical compatibility in space-constrained PCB layouts.

Technical Context

This device operates as a discrete bipolar junction transistor with fixed emitter-base-collector terminal configuration and no integrated biasing or protection circuitry. Its performance is defined by DC parameters including h_FE, V_CE(sat), and V_BE(on), alongside AC characteristics like f_T and capacitance (C_ob = 3.5–6.0 pF, C_ib = 9 pF).

It functions in linear amplification mode under V_CE ≤ 45 V and I_C ≤ 100 mA, or as a saturated switch with guaranteed V_CE(sat) ≤ 250 mV at I_C = 10 mA / I_B = 0.5 mA and ≤ 600 mV at I_C = 100 mA / I_B = 5 mA - validated per JEDEC TO-92 thermal and electrical test conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - maximum collector-emitter voltage before breakdown; defines safe operating voltage headroom in low-voltage switching rails.
I_C (DC)	100 mA - continuous collector current limit; sets upper bound for load-driving capability in relay drivers or logic-level translators.
h_FE (A grade)	110–220 - DC current gain range at V_CE = 5 V, I_C = 2 mA; determines base drive requirements for predictable saturation.
f_T	300 MHz - current gain-bandwidth product; supports small-signal amplification up to ~100 MHz with usable gain margin.
V_CE(sat)	≤250 mV @ I_C=10 mA/I_B=0.5 mA - ensures low conduction loss when used as a saturated switch in digital interface circuits.
NF	2.0–10.0 dB @ V_CE=5 V, I_C=200 μA - quantifies low-frequency noise performance suitable for preamplifier stages in audio or sensor signal chains.

Pinout & Package

BC547ATAR is housed in a standard JEDEC TO-92 3-lead plastic package with straight leads (ammo pack format), featuring 1.27 mm lead pitch and 4.6 mm body height - compatible with manual soldering and wave soldering processes.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Main current output terminal	Connected to load or higher-potential rail; must remain within 45 V absolute max and 100 mA DC limits.
2 (Base)	Control input terminal	Receives forward-biased current to enable conduction; requires series resistor to limit I_B based on h_FE and target I_C.
3 (Emitter)	Current return path	Typically grounded or tied to reference node; establishes common return for base drive and collector current loop.

Key Features

Feature	Design Value
Switching & amplification dual use	Validated across V_CE = 0.3–45 V and I_C = 10 μA–100 mA - enables reuse in both digital logic interfacing and analog signal conditioning.
Low V_CE(sat) at moderate drive	250 mV max at I_C/I_B = 20 - reduces power dissipation and heat rise in battery-powered or thermally constrained designs.
Controlled h_FE binning (A grade)	110–220 range - simplifies base resistor selection and improves consistency in production batch assembly.
JEDEC TO-92 compliance	Standardized footprint and lead form - ensures mechanical interchangeability with BC546/BC548/BC549 variants and legacy designs.

Applications

Audio Preamp Stage	Microcontroller GPIO Driver
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Small-signal NPN amplifier operating in common-emitter configuration with emitter degeneration. Use Value: 2.0–10.0 dB noise figure and 300 MHz f_T support clean gain up to 20 kHz with minimal added noise.	Use Scenario: Driving LEDs, relays, or MOSFET gates from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: Low-side saturated switch controlled by MCU GPIO pin through current-limiting base resistor. Use Value: V_CE(sat) ≤ 250 mV at I_C = 10 mA ensures <1 mW conduction loss and full logic-level compatibility.
Signal Level Shifting	Discrete Oscillator Core
Use Scenario: Translating 1.8 V logic signals to 5 V domains in mixed-voltage systems. IC Role / Device Role / Timing Role: Common-emitter level translator with pull-up resistor on collector and grounded emitter. Use Value: h_FE ≥ 110 guarantees reliable switching with sub-100 μA base current, minimizing MCU pin loading.	Use Scenario: Building Colpitts or Hartley oscillators in RF test equipment or local oscillator modules. IC Role / Device Role / Timing Role: Active gain element sustaining oscillation via tuned LC tank feedback. Use Value: 300 MHz f_T and low C_ob (3.5–6.0 pF) enable stable operation up to ~50 MHz with predictable phase margin.

Audio Preamp Stage

Microcontroller GPIO Driver

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

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

Use Value: 2.0–10.0 dB noise figure and 300 MHz f_T support clean gain up to 20 kHz with minimal added noise.

Use Scenario: Driving LEDs, relays, or MOSFET gates from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: Low-side saturated switch controlled by MCU GPIO pin through current-limiting base resistor.

Use Value: V_CE(sat) ≤ 250 mV at I_C = 10 mA ensures <1 mW conduction loss and full logic-level compatibility.

Signal Level Shifting

Discrete Oscillator Core

Use Scenario: Translating 1.8 V logic signals to 5 V domains in mixed-voltage systems.

IC Role / Device Role / Timing Role: Common-emitter level translator with pull-up resistor on collector and grounded emitter.

Use Value: h_FE ≥ 110 guarantees reliable switching with sub-100 μA base current, minimizing MCU pin loading.

Use Scenario: Building Colpitts or Hartley oscillators in RF test equipment or local oscillator modules.

IC Role / Device Role / Timing Role: Active gain element sustaining oscillation via tuned LC tank feedback.

Use Value: 300 MHz f_T and low C_ob (3.5–6.0 pF) enable stable operation up to ~50 MHz with predictable phase margin.

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 TO-92 package; h_FE bin B (200–450) instead of A (110–220); identical V_CEO, I_C, and f_T.	Higher gain enables lower base drive current but may reduce switching speed consistency in high-speed digital use.	Select BC547BTA when tighter h_FE control is needed for analog gain stability or reduced base resistor tolerance sensitivity.
PN2222A	V_CEO = 40 V (vs. 45 V), I_C = 800 mA (vs. 100 mA), h_FE = 100–300; TO-92 package with same pinout (C-B-E).	Higher current rating suits relay/motor drivers; lower V_CEO restricts use in 48 V nominal systems.	Choose PN2222A for higher-power switching where BC547ATAR's 100 mA limit is insufficient, accepting slightly reduced voltage margin.

Compared with BC547BTA and PN2222A, BC547ATAR offers the narrowest h_FE spread (110–220) among TO-92 NPN transistors in its family, enabling more deterministic base bias design in precision amplifiers - while maintaining full pinout compatibility with both alternatives.

Availability

BC547ATAR is available at Aetrix Electronics and suitable for audio preamplifiers, microcontroller GPIO drivers, signal level shifters, and discrete oscillator circuits requiring stable component supply across prototyping, industrial control, and consumer electronics production.

Supply support for BC547ATAR 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC547ATAR belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line - designed for cost-sensitive, high-volume applications requiring proven reliability, wide temperature operation, and standardized TO-92 compatibility.

FAQ

What is the maximum collector-emitter voltage rating for BC547ATAR?

The BC547ATAR has a maximum collector-emitter voltage (V_CEO) rating of 45 V at T_A = 25°C. This value is specified in the Absolute Maximum Ratings table and must not be exceeded in any operating condition to prevent device breakdown. Derating applies above 25°C ambient, with junction temperature limited to 150°C.

Does BC547ATAR have a documented h_FE range, and how is it binned?

Yes, BC547ATAR is h_FE-binned to Class A, with a guaranteed DC current gain range of 110 to 220 measured at V_CE = 5 V and I_C = 2 mA. This binning is confirmed in the Electrical Characteristics table and distinguishes it from BC547BTA (Class B: 200–450) and BC547CTA (Class C: 420–800).

What is the saturation voltage of BC547ATAR under typical switching conditions?

The BC547ATAR exhibits V_CE(sat) ≤ 250 mV when operated at I_C = 10 mA and I_B = 0.5 mA, and ≤ 600 mV at I_C = 100 mA and I_B = 5 mA. These values are specified in the Electrical Characteristics table and define conduction loss during saturated switching use.

Is BC547ATAR pin-compatible with other BC54x-series transistors?

Yes, BC547ATAR uses the standard TO-92 package with Collector-Base-Emitter pinout (pin 1 = collector, pin 2 = base, pin 3 = emitter), matching all BC546/BC547/BC548/BC549/BC550 variants. Mechanical and electrical pin compatibility is confirmed in the Physical Dimensions section and Ordering Information table.

What is the noise figure specification for BC547ATAR, and under what conditions is it measured?

The BC547ATAR 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 parameter is explicitly listed in the Electrical Characteristics table and applies to low-frequency small-signal amplification applications such as microphone preamps.

BC547ATAR Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

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

BC547ATAR FAQ

1.How can I place an order for BC547ATAR through Aetrix?

Please submit a Request for Quotation (RFQ) for BC547ATAR 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 BC547ATAR reliable?

The price and inventory of BC547ATAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC547ATAR is usually 5 days.

3.What payment methods are accepted for BC547ATAR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC547ATAR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC547ATAR?

BC547ATAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC547ATAR 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 BC547ATAR?

For technical support, including BC547ATAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC547ATAR requirements.

6.How does Aetrix verify that BC547ATAR is sourced from the original manufacturer or authorized distributors?

All BC547ATAR 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 BC547ATAR meets industry standards.

7.What is the process for return or replacement of BC547ATAR?

All BC547ATAR units undergo pre-shipment inspection (PSI). If there is an issue with BC547ATAR, 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 BC547ATAR part is unused and in its original packaging.

Return procedure for BC547ATAR:

1.Submit a request within 90 days.

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

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