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onsemi BC549TFR
- Part No.:
- BC549TFR
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
BC549TFR.pdf
- Description:
- TRANS NPN 30V 0.1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,996
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Product details
Overview
BC549TFR from ON Semiconductor is a low-noise NPN epitaxial silicon transistor in TO-92 package, rated for VCEO = 30 V, IC = 100 mA, and PC = 500 mW, with hFE range 420–800 (Class C), optimized for audio preamplifier and signal amplification stages where noise figure ≤ 4.0 dB at 200 µA/5 V is critical.
For engineers reviewing the BC549TFR datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, TO-92 terminal mapping, low-noise design implications, and validated alternative transistors for analog front-end and small-signal gain circuits.
Technical Context
The BC549TFR operates as a general-purpose NPN bipolar junction transistor with epitaxial base construction enabling improved high-frequency response (fT = 300 MHz) and reduced noise versus BC547/BC548 variants. Its low-noise specification applies specifically under VCE = 5 V, IC = 200 µA, RG = 2 kΩ, and f = 30–15,000 Hz conditions.
It shares the same TO-92 3-lead mechanical outline and pinout (1: Collector, 2: Base, 3: Emitter) across the BC546–BC550 family, but differs in absolute maximum ratings-particularly VCEO (30 V) and VCBO (30 V)-and hFE classification (Class C only).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 30 V - Maximum collector-emitter voltage before breakdown; defines safe operating range in low-voltage amplifier stages. |
| hFE (Class C) | 420–800 - DC current gain at VCE = 5 V, IC = 2 mA; enables stable biasing in high-gain common-emitter configurations. |
| Noise Figure | 1.4–4.0 dB - Measured at VCE = 5 V, IC = 200 µA, RG = 2 kΩ, 30–15,000 Hz; qualifies for low-noise microphone preamps and sensor interfaces. |
| fT | 300 MHz - Current gain bandwidth product at VCE = 5 V, IC = 10 mA; supports RF amplification up to ~100 MHz with adequate gain margin. |
| VCE(sat) | 250–600 mV - Saturation voltage at IC = 100 mA, IB = 5 mA; ensures low conduction loss in switching applications below 100 mA. |
| PC | 500 mW - Maximum power dissipation at TA = 25°C; requires thermal derating above 25°C ambient per datasheet curve. |
Pinout & Package
BC549TFR uses the standard TO-92 3-lead plastic package with straight leads (JEDEC TO-92 compliant), molded body, and 0.2″ lead spacing. Pin 1 is Collector, Pin 2 is Base, Pin 3 is Emitter - confirmed by Fairchild/ON Semiconductor mechanical drawings and ordering information.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Collector) | Output current sink node | Connected to load or next stage input; must remain within VCEO = 30 V and PC = 500 mW limits. |
| 2 (Base) | Current-controlled input | Drives transistor into active/saturation via IB; requires series resistor to limit drive current and ensure hFE-based bias stability. |
| 3 (Emitter) | Reference/output return path | Typically grounded or connected to emitter degeneration resistor; sets VBE(on) ≈ 580–700 mV at IC = 2 mA. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise operation | 1.4–4.0 dB noise figure at audio frequencies enables use in microphone preamplifiers without added noise degradation. |
| High hFE Class C grading | 420–800 DC current gain allows precise biasing with minimal base drive current, reducing loading on preceding stages. |
| 300 MHz fT | Supports stable small-signal amplification up to VHF band, suitable for IF amplifiers and oscillator buffer stages. |
| TO-92 tape-and-reel packaging (TFR) | Enables automated SMT-compatible placement despite through-hole footprint; reel quantity matches industry-standard 2,000 pcs/reel. |
Applications
| Audio Preamplifier | Signal Conditioning Amplifier |
|---|---|
|
Use Scenario: Low-level microphone or piezoelectric sensor signal amplification prior to ADC sampling. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with emitter degeneration. Use Value: 1.4–4.0 dB noise figure preserves SNR in sub-10 mVpp inputs; hFE ≥ 420 ensures stable gain over temperature. |
Use Scenario: Buffering and level-shifting analog sensor outputs (e.g., thermistor, photodiode) to microcontroller ADC inputs. IC Role / Device Role / Timing Role: Unity-gain emitter follower or fixed-gain CE stage with DC-coupled output. Use Value: VCE(sat) ≤ 600 mV and VBE(on) = 580–700 mV enable rail-to-rail compatibility with 3.3 V/5 V logic domains. |
| Oscillator Buffer Stage | Low-Power Switch Driver |
|
Use Scenario: Isolating and driving crystal oscillator output to multiple downstream clock loads without frequency pulling. IC Role / Device Role / Timing Role: High-impedance input buffer followed by low-output-impedance emitter follower. Use Value: fT = 300 MHz and Cob ≤ 6.0 pF minimize phase shift and capacitive loading on resonant circuit. |
Use Scenario: Driving LED indicators, relays, or small solenoids from MCU GPIO pins with current gain > 400. IC Role / Device Role / Timing Role: Saturated switch with base overdrive to ensure VCE(sat) ≤ 250 mV at IC = 10 mA. Use Value: 500 mW power rating and 100 mA IC limit support continuous 20 mA LED drive with 2.5× safety margin. |
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 |
|---|---|---|---|
| BC549CTA | Same die, TO-92 ammo pack (not tape-and-reel); identical VCEO, hFE, noise, and pinout. | No difference in circuit function; only packaging format differs (bulk vs. TFR). | Select BC549CTA for manual prototyping or low-volume hand assembly; BC549TFR for automated production. |
| 2N5088 | Higher VCEO = 30 V (same), but lower hFE min = 300, higher noise figure (≈ 5 dB), and no Class C grading. | Acceptable for non-critical amplification, but not recommended where < 4.0 dB noise or guaranteed hFE ≥ 420 is required. | Use 2N5088 only if BC549TFR supply is constrained and noise/gain margins can be relaxed. |
Compared with BC549CTA, BC549TFR offers identical electrical performance with SMT-ready tape-and-reel delivery; versus 2N5088, BC549TFR provides superior noise performance and tighter hFE control essential for precision analog gain stages.
Availability
BC549TFR is available at Aetrix Electronics and suitable for audio preamplifiers, sensor signal conditioning circuits, and low-power switching applications requiring stable component supply, consistent hFE grading, and low-noise transistor performance.
Supply support for BC549TFR 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 (formerly Fairchild Semiconductor) is a global supplier of energy-efficient semiconductor components, specializing in power management, analog, and discrete devices for automotive, industrial, and consumer markets.
The BC549TFR belongs to the legacy BC546–BC550 NPN transistor family, designed for general-purpose amplification and switching in cost-sensitive, high-reliability analog circuits where low noise and predictable hFE are prioritized.
FAQ
What is the pinout configuration of BC549TFR?
The BC549TFR uses the standard TO-92 3-lead package with pin 1 as Collector, pin 2 as Base, and pin 3 as Emitter - confirmed by Fairchild/ON Semiconductor mechanical drawings and ordering documentation. This pinout is consistent across all BC546–BC550 variants and matches JEDEC TO-92 specifications. No alternate pinouts or package variants exist for BC549TFR.
Does BC549TFR have a specified noise figure, and under what conditions?
Yes, BC549TFR has a noise figure of 1.4–4.0 dB, measured at VCE = 5 V, IC = 200 µA, RG = 2 kΩ, and frequency range 30–15,000 Hz. This specification is explicitly assigned to BC549 and BC550 in the datasheet and distinguishes them from BC546–BC548, which have higher noise figures. The BC549TFR maintains this value as a Class C device.
What is the hFE range for BC549TFR, and how is it graded?
The BC549TFR is graded as Class C, with hFE ranging from 420 to 800 at VCE = 5 V and IC = 2 mA. This grading is confirmed in the "hFE Classification" table of the BC546–BC550 datasheet and applies specifically to BC549C and BC550C variants. BC549TFR is the tape-and-reel version of BC549C, retaining identical electrical binning.
Can BC549TFR replace BC547BTF in a low-noise circuit?
No - BC549TFR is not a direct replacement for BC547BTF in low-noise applications. While both are TO-92 NPN transistors, BC547B has a noise figure of 2.0–10.0 dB (worse than BC549's 1.4–4.0 dB) and lower hFE (200–450 vs. 420–800). Substituting BC549TFR may improve noise and gain, but requires verification of VCEO (30 V vs. 45 V) and bias point compatibility in the target circuit.
What does the "TFR" suffix indicate in BC549TFR?
The "TFR" suffix in BC549TFR denotes Tape-and-Reel packaging with 2,000 units per reel, optimized for automated pick-and-place assembly. It corresponds electrically and mechanically to the BC549C variant - same silicon die, TO-92 package, pinout, and full parameter set. "TFR" replaces older "TF" or "TA" codes to align with ON Semiconductor's updated nomenclature post-Fairchild integration.
BC549TFR 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
BC549TFR FAQ
1.How can I place an order for BC549TFR through Aetrix?
Please submit a Request for Quotation (RFQ) for BC549TFR 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 BC549TFR reliable?
The price and inventory of BC549TFR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC549TFR is usually 5 days.
3.What payment methods are accepted for BC549TFR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC549TFR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC549TFR?
BC549TFR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC549TFR 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 BC549TFR?
For technical support, including BC549TFR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC549TFR requirements.
6.How does Aetrix verify that BC549TFR is sourced from the original manufacturer or authorized distributors?
All BC549TFR 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 BC549TFR meets industry standards.
7.What is the process for return or replacement of BC549TFR?
All BC549TFR units undergo pre-shipment inspection (PSI). If there is an issue with BC549TFR, 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 BC549TFR part is unused and in its original packaging.
Return procedure for BC549TFR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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