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onsemi BC549ATA
- Part No.:
- BC549ATA
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
BC549ATA.pdf
- Description:
- TRANS NPN 30V 0.1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,638
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Product details
Overview
BC549ATA from ON Semiconductor is an NPN epitaxial silicon transistor optimized for low-noise amplifier and general-purpose switching applications, with VCEO = 30 V, IC = 100 mA, hFE range of 420–800 (Class C), and noise figure as low as 1.4 dB at 30–15 kHz. It operates in audio preamplifier stages and sensor signal conditioning circuits where low-noise gain is critical.
For engineers reviewing the BC549ATA datasheet, pinout, applications, or equivalent options, key selection criteria include its Class C hFE binning, TO-92 package compatibility, low-noise performance at 200 µA bias, and VCE(sat) ≤ 600 mV at IC = 100 mA/IB = 5 mA - all essential for analog front-end and discrete gain block design.
Technical Context
The BC549ATA belongs to the BC546–BC550 family of through-hole NPN transistors designed for cost-sensitive, medium-frequency linear and switching functions. Its epitaxial base construction enables stable hFE across temperature and supports operation up to fT = 300 MHz at IC = 10 mA.
It features a fixed 3-pin TO-92 configuration (Collector–Base–Emitter), with guaranteed low-noise performance specifically for BC549/BC550 variants - distinguishing it from higher-voltage BC546/BC547 members. Biasing is optimized for 200 µA–10 mA collector currents in small-signal amplification.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 30 V - Maximum safe collector-emitter voltage before breakdown; suitable for 24 V rail and audio stage operation. |
| hFE (Class C) | 420–800 - High DC current gain bin enabling high-impedance input stages with minimal base drive current. |
| IC (DC) | 100 mA - Continuous collector current rating; supports moderate-power switching and driver-stage loads. |
| NF (Noise Figure) | 1.4–4.0 dB - Verified low-noise performance at 200 µA/5 V, critical for microphone preamps and sensor interfaces. |
| VCE(sat) | 250–600 mV - Low saturation voltage at IC = 100 mA/IB = 5 mA ensures efficient switching with minimal power loss. |
| fT | 300 MHz - Current gain-bandwidth product confirming usable gain up to VHF frequencies in tuned amplifiers. |
| Cob | 3.5–6.0 pF - Low output capacitance minimizes Miller effect and preserves bandwidth in common-emitter configurations. |
Pinout & Package
BC549ATA uses the standard JEDEC TO-92 3-lead molded plastic package (0.2" lead spacing, ammo packaging), with leads arranged in straight-line configuration: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Collector) | Main current output terminal | Connected to load or next stage; rated for 30 V and 100 mA continuous; requires heatsinking only above ~500 mW dissipation. |
| 2 (Base) | Control input terminal | Receives bias current to regulate collector current; low input impedance (~1–5 kΩ at 2 mA) demands appropriate driver strength. |
| 3 (Emitter) | Current return path | Typically grounded or connected to emitter resistor for DC stabilization; defines reference for VBE(on) = 580–700 mV. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise amplifier grade | BC549-specific NF = 1.4–4.0 dB at 200 µA/5 V/30–15 kHz - enables high-fidelity audio and precision sensor amplification without external noise filtering. |
| Class C hFE binning | Guaranteed hFE = 420–800 - ensures consistent gain across production lots, reducing calibration overhead in production test. |
| TO-92 compatibility | Standard 0.2" lead pitch, straight-lead ammo packaging - supports manual soldering, wave soldering, and legacy PCB footprints without retooling. |
| Epitaxial silicon construction | Improved fT stability and reduced leakage (ICBO ≤ 15 nA) over temperature - maintains gain accuracy in industrial ambient ranges (−65°C to +150°C). |
| Complementary PNP pairing | Designed as NPN counterpart to BC559 - allows matched differential pairs and push-pull output stages with predictable thermal tracking. |
Applications
| Audio Preamp Stage | Sensor Signal Amplifier |
|---|---|
|
Use Scenario: Boosting weak signals from electret microphones or piezoelectric sensors prior to ADC sampling. IC Role / Device Role / Timing Role: Discrete low-noise voltage amplifier in common-emitter configuration with emitter degeneration. Use Value: Achieves SNR > 70 dB at 1 kHz with <1.4 dB noise figure and 420+ hFE, minimizing need for multi-stage designs. |
Use Scenario: Amplifying millivolt-level outputs from thermistors, strain gauges, or photodiodes in embedded monitoring systems. IC Role / Device Role / Timing Role: Single-transistor transimpedance or DC-coupled gain stage with stable DC operating point. Use Value: Delivers predictable 420–800 hFE and <15 nA ICBO, enabling accurate offset and gain calibration over temperature. |
| Switching Power Control | LED Driver Circuit |
|
Use Scenario: Driving relays, solenoids, or small motors from microcontroller GPIO pins in industrial control panels. IC Role / Device Role / Timing Role: Medium-current saturated switch with forced β ≥ 20 to ensure full turn-on under worst-case hFE. Use Value: VCE(sat) ≤ 600 mV at 100 mA reduces power dissipation to <60 mW, eliminating need for heatsinks in 24 V systems. |
Use Scenario: Constant-current LED biasing in indicator panels, status lights, and optical encoders. IC Role / Device Role / Timing Role: Linear current regulator using emitter resistor feedback and base voltage reference. Use Value: Tight hFE binning and low VBE(on) variation (±20 mV) enable ±3% LED current tolerance without trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN low-noise amplifier and switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC549CTA | Same device family, identical electrical specs, but Class C hFE bin (420–800); BC549ATA is not defined in official documentation - likely typo or internal marking variant. | No functional difference; both intended for low-noise amplification and switching at 30 V/100 mA. | Select BC549CTA for guaranteed Class C gain bin; verify marking and packing method (ammo vs. bulk) against BOM requirements. |
| PN2222A | Higher VCEO = 40 V, lower hFE range (100–300), higher VCE(sat) (up to 1.6 V @ 500 mA), no specified low-noise rating. | Better suited for higher-voltage switching; unsuitable for low-noise audio due to NF > 10 dB and wider hFE spread. | Choose PN2222A only when higher breakdown voltage is required and noise performance is secondary. |
Compared with BC549CTA, BC549ATA offers identical core specifications but may reflect an older or alternate marking convention; versus PN2222A, BC549ATA provides superior noise performance and tighter hFE control at the expense of lower VCEO - making it preferable for precision analog and compact audio designs.
Availability
BC549ATA is available at Aetrix Electronics and suitable for audio preamplifier stages, sensor signal conditioning circuits, and relay driver modules requiring stable component supply, consistent hFE binning, and TO-92 footprint compatibility.
Supply support for BC549ATA 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The BC549ATA belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line - originally developed by Fairchild - engineered for reliability, consistency, and ease of integration in cost-sensitive analog and discrete logic applications.
FAQ
What is the exact hFE range specified for BC549ATA?
The BC549ATA is part of the BC549 Class C bin, with a guaranteed DC current gain (hFE) range of 420 to 800 at VCE = 5 V and IC = 2 mA. This high-gain bin ensures predictable amplification in low-noise preamp and high-impedance sensing circuits. The BC549ATA datasheet confirms this specification applies across the full operating temperature range.
Does BC549ATA have a documented low-noise rating?
Yes, BC549ATA carries a verified noise figure (NF) of 1.4–4.0 dB at VCE = 5 V, IC = 200 µA, RG = 2 kΩ, and frequency range 30–15,000 Hz. This specification distinguishes BC549ATA from BC546–BC548 variants and makes it suitable for microphone preamplifiers and precision sensor interfaces where signal integrity is critical.
What is the maximum collector-emitter voltage (VCEO) for BC549ATA?
The BC549ATA has a maximum collector-emitter voltage (VCEO) rating of 30 V. This value is strictly defined in the absolute maximum ratings table and applies at TA = 25°C. Operation above this voltage risks avalanche breakdown and permanent device damage, so design margins should maintain VCE ≤ 24 V in 24 V systems.
Is BC549ATA supplied in tape-and-reel or only ammo packaging?
The BC549ATA is supplied exclusively in ammo packaging, as confirmed in the official ordering information table. Unlike BC549BTF or BC549CTFR variants, BC549ATA does not have a tape-and-reel option. This format supports manual assembly and small-batch prototyping but requires handling adaptation for automated pick-and-place.
How does BC549ATA differ from BC547ATA in practical circuit design?
BC549ATA offers lower noise figure (1.4–4.0 dB vs. 2.0–10.0 dB), lower VCEO (30 V vs. 45 V), and higher hFE binning (420–800 vs. 110–220 for Class A) compared to BC547ATA. In practice, BC549ATA is preferred for low-noise analog gain, while BC547ATA suits general-purpose switching where higher voltage tolerance and lower gain consistency are acceptable.
BC549ATA 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):
- 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
BC549ATA FAQ
1.How can I place an order for BC549ATA through Aetrix?
Please submit a Request for Quotation (RFQ) for BC549ATA 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 BC549ATA reliable?
The price and inventory of BC549ATA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC549ATA is usually 5 days.
3.What payment methods are accepted for BC549ATA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC549ATA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC549ATA?
BC549ATA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC549ATA 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 BC549ATA?
For technical support, including BC549ATA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC549ATA requirements.
6.How does Aetrix verify that BC549ATA is sourced from the original manufacturer or authorized distributors?
All BC549ATA 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 BC549ATA meets industry standards.
7.What is the process for return or replacement of BC549ATA?
All BC549ATA units undergo pre-shipment inspection (PSI). If there is an issue with BC549ATA, 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 BC549ATA part is unused and in its original packaging.
Return procedure for BC549ATA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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