My Inquiry
My Account
onsemi BC549CTFR
- Part No.:
- BC549CTFR
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
BC549CTFR.pdf
- Description:
- TRANS NPN 30V 0.1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,820
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
BC549CTFR from ON Semiconductor is an NPN epitaxial silicon transistor optimized for low-noise amplification and general-purpose switching in analog signal paths, audio preamplifiers, and sensor interface circuits; features hFE 420–800 (Class C), VCEO = 30 V, IC = 100 mA, fT = 300 MHz, and NF = 1.4–4.0 dB at 30–15 kHz.
For engineers reviewing the BC549CTFR datasheet, pinout, applications, or equivalent options, key selection criteria include low-noise performance at microamp bias currents, TO-92 package compatibility with through-hole prototyping, DC current gain linearity across collector loads, and saturation voltage behavior under 10 mA/100 mA drive conditions.
Technical Context
The BC549CTFR operates as a discrete bipolar junction transistor with fixed emitter-base and collector-base junction geometry, supporting linear amplification when biased in the active region and fast switching when driven into saturation or cutoff. Its epitaxial base construction enables stable hFE over temperature and reduced 1/f noise compared to diffused-base variants.
Designed for single-supply operation up to 30 V, it delivers predictable VBE(on) of 580–700 mV at IC = 2 mA and VCE = 5 V, with Cob ≤ 6.0 pF and Cib ≈ 9 pF enabling RF-coupled stage design up to ~100 MHz. Noise figure is specified under standardized 2 kΩ source impedance and 200 μA collector current conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 30 V - Maximum safe collector-emitter voltage before breakdown; sets upper rail limit for amplifier stages and switch drivers. |
| hFE (Class C) | 420–800 - High DC current gain range ensures stable biasing with minimal base drive current in low-power analog circuits. |
| NF | 1.4–4.0 dB @ 30–15 kHz - Confirmed low-noise performance critical for microphone preamps and precision sensor front-ends. |
| fT | 300 MHz - Unity-gain bandwidth supports small-signal amplification up to VHF frequencies with adequate gain margin. |
| IC(max) | 100 mA - Continuous collector current rating defines maximum load-handling capability in switching applications. |
| PC | 500 mW - Power dissipation limit at TA = 25°C; requires thermal derating above 25°C ambient per datasheet curve. |
| Cob | 3.5–6.0 pF - Output capacitance impacts high-frequency roll-off and stability in common-emitter configurations. |
Pinout & Package
BC549CTFR uses the standard TO-92 3-lead plastic package with straight leads (JEDEC TO-92 compliant), suitable for manual soldering and wave soldering in through-hole PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Top View) | Collector | Main current sink terminal; connects to load or supply rail in common-emitter configuration. |
| 2 (Top View) | Base | Control input; requires current-limited drive to achieve target hFE-dependent collector current. |
| 3 (Top View) | Emitter | Current source terminal; typically tied to ground or negative rail in single-supply designs. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise amplification | Verified NF = 1.4–4.0 dB at 200 μA/2 kΩ source, enabling high-fidelity audio and sensor signal conditioning without added op-amp stages. |
| High hFE Class C grading | Guaranteed 420–800 hFE ensures consistent bias point stability across production lots in linear amplifier designs. |
| TO-92 tape-and-reel packaging | BC549CTFR is supplied in EIA-481-compliant tape-and-reel format (3,000 pcs/reel), supporting automated SMT placement with manual rework compatibility. |
| Epitaxial silicon construction | Delivers improved fT consistency, lower leakage (ICBO ≤ 15 nA), and tighter hFE distribution versus diffused-base alternatives. |
Applications
| Audio Pre-amplifier Stage | Sensor Signal Conditioning |
|---|---|
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric transducers in battery-powered voice recorders. IC Role / Device Role / Timing Role: NPN small-signal amplifier operating in common-emitter configuration with emitter degeneration for linearity. Use Value: Low NF (1.4–4.0 dB) and high hFE minimize required gain stages and preserve SNR without external noise-filtering components. | Use Scenario: Converting low-level output from thermistors, photodiodes, or strain gauges into robust voltage levels for ADC input. IC Role / Device Role / Timing Role: Transimpedance or voltage-amplifier stage with adjustable gain via collector resistor and emitter bias network. Use Value: Stable hFE (420–800) and low ICBO (<15 nA) ensure accurate, drift-free amplification across industrial temperature ranges. |
| General-Purpose Switching | LED Driver Interface |
Use Scenario: Controlling relay coils, small solenoids, or logic-level MOSFET gates in PLC I/O modules and embedded control panels. IC Role / Device Role / Timing Role: Saturated switch with base current limiting to ensure full turn-on and low VCE(sat) < 250 mV at 10 mA. Use Value: Guaranteed VCE(sat) ≤ 250 mV at IC = 10 mA/IB = 0.5 mA reduces power loss and heat generation in high-duty-cycle switching. | Use Scenario: Driving indicator LEDs or status lamps from microcontroller GPIO pins with current limiting and level translation. IC Role / Device Role / Timing Role: Current-buffering switch configured in common-emitter mode with fixed emitter resistor. Use Value: IC(max) = 100 mA and PC = 500 mW support simultaneous driving of multiple LEDs without external heat sinking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN small-signal transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC549C (TO-92, Ammo) | Identical electrical specs and hFE grading; differs only in packaging (ammo vs. tape-and-reel). | No functional difference; choice depends on assembly method-tape-and-reel for automated placement, ammo for hand-soldering or low-volume builds. | Select BC549CTFR when using pick-and-place equipment; choose BC549C for manual assembly or prototype runs. |
| 2N3904 | Lower hFE range (100–300), higher VCEO (40 V), slightly higher NF (5 dB typical), same TO-92 package. | Better suited for higher-voltage switching but less optimal for low-noise, high-gain analog stages where BC549CTFR's Class C hFE and sub-4 dB NF provide advantage. | Prefer BC549CTFR for noise-sensitive amplification; use 2N3904 where higher breakdown voltage or legacy design compatibility is required. |
Compared with BC549C (ammo) and 2N3904, BC549CTFR offers superior low-noise performance and guaranteed high hFE for precision analog gain, while maintaining identical footprint and assembly compatibility with TO-92 tape-and-reel automation workflows.
Availability
BC549CTFR is available at Aetrix Electronics and suitable for audio pre-amplifier design, sensor interface circuits, general-purpose switching, and LED driver interfaces requiring stable component supply and long-term manufacturability.
Supply support for BC549CTFR 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 devices for automotive, industrial, and consumer applications.
The BC549CTFR belongs to ON Semiconductor's legacy general-purpose transistor product line, originally developed by Fairchild and maintained for cost-sensitive, high-reliability analog and switching functions in mass-produced electronics.
FAQ
What is the pin configuration of BC549CTFR?
The BC549CTFR uses the 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 configuration is consistent across all BC54x series transistors and verified in the official ON Semiconductor datasheet Rev. 1.1.1.
What does the 'TFR' suffix mean in BC549CTFR?
The 'TFR' suffix in BC549CTFR indicates Tape-and-Reel packaging per EIA-481 standards, with 3,000 units per reel. It confirms the device is supplied in automated assembly-ready format, distinct from bulk (BU) or ammo (TA) variants of the same BC549C die.
Is BC549CTFR suitable for low-noise audio applications?
Yes, BC549CTFR is explicitly rated for low-noise operation with NF = 1.4–4.0 dB at 30–15 kHz under standardized 200 μA/2 kΩ conditions. Its Class C hFE grading and epitaxial base structure make it well-suited for microphone preamplifiers and other high-SNR analog signal chains.
What is the maximum collector-emitter voltage rating for BC549CTFR?
The BC549CTFR has a VCEO rating of 30 V, meaning it can safely withstand up to 30 volts between collector and emitter terminals with base open. This value is confirmed in the Absolute Maximum Ratings table of the ON Semiconductor BC546–BC550 datasheet Rev. 1.1.1.
How does BC549CTFR compare to BC547CTFR in terms of noise performance?
BC549CTFR has superior noise performance versus BC547CTFR: BC549CTFR specifies NF = 1.4–4.0 dB (30–15 kHz), while BC547CTFR is rated at 2.0–10.0 dB under broader 1 kHz conditions. The BC549 variant is specifically optimized for low-noise applications, unlike the general-purpose BC547.
BC549CTFR 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:
- 420 @ 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
BC549CTFR FAQ
1.How can I place an order for BC549CTFR through Aetrix?
Please submit a Request for Quotation (RFQ) for BC549CTFR 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 BC549CTFR reliable?
The price and inventory of BC549CTFR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC549CTFR is usually 5 days.
3.What payment methods are accepted for BC549CTFR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC549CTFR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC549CTFR?
BC549CTFR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC549CTFR 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 BC549CTFR?
For technical support, including BC549CTFR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC549CTFR requirements.
6.How does Aetrix verify that BC549CTFR is sourced from the original manufacturer or authorized distributors?
All BC549CTFR 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 BC549CTFR meets industry standards.
7.What is the process for return or replacement of BC549CTFR?
All BC549CTFR units undergo pre-shipment inspection (PSI). If there is an issue with BC549CTFR, 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 BC549CTFR part is unused and in its original packaging.
Return procedure for BC549CTFR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC549CTFR Tags
-
MMBT3906LT1G
onsemi
-
MMBT3904-7-F
Diodes Incorporated
-
MMBT3904LT1G
onsemi
-
MMBT3906-7-F
Diodes Incorporated
-
MMBT3904-TP
Micro Commercial Co
-
MMBT2222A-7-F
Diodes Incorporated
-
BC846BLT1G
onsemi
-
BC847B,215
Nexperia USA Inc.
-
SMMBT3904LT1G
onsemi
-
MMBT2222A-TP
Micro Commercial Co
-
MMBTA06LT1G
onsemi
-
MMBT2222ALT1G
onsemi
Tech Hub
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, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
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.
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.
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…
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…
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…
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 …
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…
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…
