Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi BC548ATF

Name: BC548ATF
Brand: onsemi
SKU: BC548ATF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BC548ATF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC548ATF.pdf

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

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:8,574

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BC548ATF from ON Semiconductor is an NPN epitaxial silicon transistor designed for general-purpose switching and low-noise amplification in discrete analog circuits. It features V_CEO = 30 V, I_C = 100 mA, h_FE (Class B) = 200–450, f_T = 300 MHz, and TO-92 package - commonly used in audio preamplifiers, sensor signal conditioning, and digital logic interface stages.

For engineers reviewing the BC548ATF datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain classification (B), saturation voltage at 10 mA/0.5 mA drive, noise figure at 1 kHz, output capacitance, and compatibility with legacy BC-series designs requiring TO-92 footprint and lead-form consistency.

Technical Context

This device operates as a single NPN bipolar junction transistor with epitaxial base construction, optimized for stable h_FE across temperature and low 1/f noise performance. Its V_CEO = 30 V and V_CBO = 30 V rating suit medium-voltage signal routing and low-power switching up to 500 mW dissipation.

The BC548ATF belongs to the BC546–BC550 family sharing identical TO-92 3L mechanical form factor and pinout (C-B-E), but differentiated by voltage ratings and h_FE bins. It is not a drop-in replacement for BC546/BC547 due to lower breakdown voltages and distinct h_FE distribution.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum collector-emitter voltage before breakdown; defines safe operating range in common-emitter amplifier or switch configurations.
I_C (DC)	100 mA - Continuous collector current limit; determines maximum load drive capability in switching applications.
h_FE (Class B)	200–450 - DC current gain bin at V_CE = 5 V, I_C = 2 mA; enables predictable biasing in linear amplifiers without gain variation compensation.
f_T	300 MHz - Current gain bandwidth product; supports small-signal amplification up to VHF band in RF front-end or oscillator buffer stages.
NF (1 kHz)	2.0–10.0 dB - Noise figure at V_CE = 5 V, I_C = 200 μA, R_G = 2 kΩ; suitable for low-noise preamp stages in microphone or sensor interfaces.
V_CE(sat)	90–250 mV @ I_C = 10 mA, I_B = 0.5 mA - Low saturation voltage ensures minimal power loss and high efficiency in saturated-switch operation.
P_C	500 mW - Maximum power dissipation at T_A = 25°C; sets thermal design margin for PCB copper area and ambient temperature derating.

Pinout & Package

BC548ATF is housed in a JEDEC-standard TO-92 3-lead plastic package with straight leads (ammo pack configuration). The case outline conforms to Fairchild/ON Semiconductor specification for through-hole mounting and manual soldering.

Pin/Terminal	Circuit Role	Design Meaning
1 (Top View)	Collector	Main current sink terminal; connects to load or supply rail in common-emitter or common-base topologies.
2 (Center)	Base	Control electrode; requires current-limited drive (typically via resistor) to regulate collector current proportionally to h_FE.
3 (Bottom)	Emitter	Current source terminal; usually tied to ground or negative rail; provides reference for V_BE biasing and emitter degeneration.

Key Features

Feature	Design Value
TO-92 3L package	Standardized through-hole footprint compatible with legacy BC-series layouts and automated insertion equipment.
h_FE Class B bin	Guaranteed 200–450 gain range enables consistent bias point setting without individual transistor sorting in production.
Low V_CE(sat)	Sub-250 mV saturation voltage at 10 mA drive reduces conduction loss and improves switching efficiency in digital logic level translation.
300 MHz f_T	Supports stable small-signal amplification up to ~100 MHz with adequate gain margin, suitable for IF amplifiers and oscillator buffers.
Low 1 kHz noise figure	2–10 dB NF allows use in first-stage audio preamps where signal integrity dominates over power handling.

Applications

Audio Preamp Stage	Sensor Signal Amplifier
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors prior to ADC sampling. IC Role / Device Role / Timing Role: Discrete NPN transistor configured in common-emitter topology with emitter degeneration for linearity and gain stability. Use Value: BC548ATF's 200–450 h_FE bin and 2–10 dB noise figure enable high-SNR amplification without active feedback complexity.	Use Scenario: Boosting millivolt-level outputs from temperature or pressure transducers in industrial monitoring systems. IC Role / Device Role / Timing Role: Single-transistor non-inverting amplifier with fixed bias network and bypassed emitter resistor. Use Value: BC548ATF's low V_CE(sat) and stable h_FE ensure accurate gain scaling across temperature without trimming.
Digital Logic Interface	Low-Power Switch Driver
Use Scenario: Level-shifting 3.3 V MCU GPIO outputs to drive 5 V TTL-compatible inputs or LED indicators. IC Role / Device Role / Timing Role: Saturated NPN switch with base resistor limiting I_B to ensure full turn-on and fast edge response. Use Value: BC548ATF's 90–250 mV V_CE(sat) minimizes voltage drop and power loss while maintaining clean logic thresholds.	Use Scenario: Controlling small solenoids, relays, or indicator lamps from microcontroller I/O pins. IC Role / Device Role / Timing Role: Medium-current switching element with flyback diode protection and current-limiting base drive. Use Value: BC548ATF's 100 mA I_C rating and 500 mW P_C support reliable on/off cycling of 20–80 mA loads at room temperature.

Audio Preamp Stage

Sensor Signal Amplifier

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

IC Role / Device Role / Timing Role: Discrete NPN transistor configured in common-emitter topology with emitter degeneration for linearity and gain stability.

Use Value: BC548ATF's 200–450 h_FE bin and 2–10 dB noise figure enable high-SNR amplification without active feedback complexity.

Use Scenario: Boosting millivolt-level outputs from temperature or pressure transducers in industrial monitoring systems.

IC Role / Device Role / Timing Role: Single-transistor non-inverting amplifier with fixed bias network and bypassed emitter resistor.

Use Value: BC548ATF's low V_CE(sat) and stable h_FE ensure accurate gain scaling across temperature without trimming.

Digital Logic Interface

Low-Power Switch Driver

Use Scenario: Level-shifting 3.3 V MCU GPIO outputs to drive 5 V TTL-compatible inputs or LED indicators.

IC Role / Device Role / Timing Role: Saturated NPN switch with base resistor limiting I_B to ensure full turn-on and fast edge response.

Use Value: BC548ATF's 90–250 mV V_CE(sat) minimizes voltage drop and power loss while maintaining clean logic thresholds.

Use Scenario: Controlling small solenoids, relays, or indicator lamps from microcontroller I/O pins.

IC Role / Device Role / Timing Role: Medium-current switching element with flyback diode protection and current-limiting base drive.

Use Value: BC548ATF's 100 mA I_C rating and 500 mW P_C support reliable on/off cycling of 20–80 mA loads at room temperature.

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	V_CEO = 45 V (vs. 30 V); same h_FE Class B bin and TO-92 package.	Higher voltage headroom suits 5–12 V rail applications where BC548ATF may approach breakdown limits.	Select BC547BTA when operating above 30 V collector swing or requiring extended safe operating area.
BC548CTA	h_FE = 420–800 (Class C); otherwise identical voltage/current ratings and package.	Higher gain enables reduced base drive current and improved sensitivity in low-power amplifier stages.	Choose BC548CTA when higher h_FE is required for low-bias or battery-operated designs without changing layout.

Compared with BC547BTA and BC548CTA, the BC548ATF offers a balanced trade-off between voltage rating and gain - making it optimal for cost-sensitive, space-constrained designs where 30 V operation and mid-range h_FE meet system requirements without over-specifying.

Availability

BC548ATF is available at Aetrix Electronics and suitable for audio preamplifiers, sensor signal conditioners, and digital logic interface circuits requiring stable component supply and long-term obsolescence management.

Supply support for BC548ATF 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, sensor, and discrete solutions for automotive, industrial, and consumer markets.

The BC548ATF belongs to ON Semiconductor's legacy general-purpose transistor portfolio, originally developed by Fairchild and maintained for backward compatibility in cost-sensitive, high-volume linear and switching applications.

FAQ

What is the pinout configuration of BC548ATF?

The BC548ATF uses a standard TO-92 package with pin 1 as Collector, pin 2 as Base, and pin 3 as Emitter when viewed with flat side facing outward and leads pointing downward. This matches JEDEC TO-92 straight-lead orientation and is identical across the BC546–BC550 family. Always verify orientation using the marking dot or notch on the package body before PCB layout or assembly.

Does BC548ATF have a specified noise figure, and under what conditions?

Yes, BC548ATF has a noise figure 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 value applies specifically to the BC548 variant (not BC549/BC550), and reflects its suitability for low-noise preamplifier stages where signal integrity is critical and source impedance is near 2 kΩ.

What is the maximum collector current rating for BC548ATF, and how does it relate to power dissipation?

The BC548ATF has a maximum DC collector current rating of 100 mA and a maximum collector power dissipation of 500 mW at T_A = 25°C. At full 100 mA, the device must maintain V_CE ≤ 5 V to stay within P_C limit. Derating is required above 25°C ambient - approximately 4.5 mW/°C - to prevent thermal runaway or junction overheating beyond 150°C.

How does BC548ATF differ from BC548CTA in terms of DC current gain?

The BC548ATF is classified as h_FE Class B (200–450), while BC548CTA is Class C (420–800), both tested at V_CE = 5 V and I_C = 2 mA. This means BC548CTA delivers higher and more tightly bounded gain, enabling lower base drive current and improved sensitivity in amplifier designs - but with no change to voltage, current, or package specifications.

Is BC548ATF suitable for RF amplifier applications, and what is its frequency limit?

Yes, BC548ATF supports RF amplifier use up to approximately 100 MHz due to its 300 MHz current gain bandwidth product (f_T). It is validated for small-signal amplification at V_CE = 5 V, I_C = 10 mA, and f = 100 MHz. Performance degrades above this frequency due to decreasing h_FE, so it is not recommended for UHF or microwave stages where f_T > 1 GHz is required.

BC548ATF Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

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:: 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

BC548ATF FAQ

1.How can I place an order for BC548ATF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC548ATF 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 BC548ATF reliable?

The price and inventory of BC548ATF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC548ATF is usually 5 days.

3.What payment methods are accepted for BC548ATF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC548ATF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC548ATF?

BC548ATF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC548ATF 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 BC548ATF?

For technical support, including BC548ATF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC548ATF requirements.

6.How does Aetrix verify that BC548ATF is sourced from the original manufacturer or authorized distributors?

All BC548ATF 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 BC548ATF meets industry standards.

7.What is the process for return or replacement of BC548ATF?

All BC548ATF units undergo pre-shipment inspection (PSI). If there is an issue with BC548ATF, 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 BC548ATF part is unused and in its original packaging.

Return procedure for BC548ATF:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…