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onsemi BC550ATA
- Part No.:
- BC550ATA
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
BC550ATA.pdf
- Description:
- TRANS NPN 45V 0.1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,956
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Product details
Overview
BC550ATA from ON Semiconductor is an NPN epitaxial silicon transistor optimized for low-noise amplification and general-purpose switching in analog signal paths, with VCEO = 45 V, IC = 100 mA, hFE = 420–800 (Class C), and NF = 1.4–3.0 dB at 1 kHz. It operates in TO-92 package and is commonly used in audio preamplifiers, sensor interface stages, and biasing circuits requiring stable gain and minimal noise contribution.
For engineers reviewing the BC550ATA datasheet, pinout, applications, or equivalent options, key selection considerations include its Class C hFE range, low-noise performance versus BC549/BC547 variants, TO-92 lead configuration, and compatibility with legacy BC-series designs requiring VCEO ≥ 45 V and fT ≥ 300 MHz.
Technical Context
The BC550ATA belongs to the BC546–BC550 family of through-hole NPN transistors sharing identical TO-92 packaging and pinout (C-B-E), but differentiated by voltage ratings and noise performance. BC550 specifically targets low-noise linear applications, with VEBO = 5 V, VCEO = 45 V, and guaranteed hFE ≥ 420 at IC = 2 mA.
Its fT = 300 MHz ensures usable bandwidth in audio and RF front-end stages up to ~100 MHz, while Cob = 3.5–6.0 pF and Cib = 9 pF support stable high-frequency biasing. The device is not rated for switching speeds above 10 MHz due to saturation delay and storage time limitations inherent to its epitaxial construction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 45 V - Maximum collector-emitter voltage before breakdown; supports rail-to-rail operation in ±20 V analog supplies. |
| hFE (Class C) | 420–800 - DC current gain at VCE = 5 V, IC = 2 mA; enables high-gain single-stage amplification without cascading. |
| NF | 1.4–3.0 dB - Noise figure at VCE = 5 V, IC = 200 μA, f = 1 kHz, RG = 2 kΩ; suitable for microphone preamps and instrumentation front-ends. |
| fT | 300 MHz - Current gain-bandwidth product; defines small-signal AC response limit for amplifier design. |
| VCBO | 50 V - Collector-base breakdown voltage; determines maximum reverse bias across base-collector junction during cutoff. |
| PC | 500 mW - Maximum power dissipation at TA = 25°C; requires thermal derating above 25°C ambient per datasheet curve. |
Pinout & Package
BC550ATA uses the standard TO-92 3-lead plastic package with straight leads (JEDEC TO-92 compliant). Dimensions conform to Figure 7 and Figure 8 in the datasheet, with lead spacing of 0.2 inch (5.08 mm) and body height ≤ 4.7 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Top View) | Collector | Main current sink terminal; connects to load or supply rail in common-emitter configurations. |
| 2 (Center) | Base | Control input; requires current-limited drive (IB ≤ 5 mA typical) to avoid saturation-induced storage delay. |
| 3 (Bottom) | Emitter | Current source terminal; often tied to ground or negative rail; sets bias point via emitter resistor. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise amplification | NF = 1.4–3.0 dB at 1 kHz enables high-fidelity audio signal conditioning without added background hiss. |
| High DC current gain (Class C) | hFE ≥ 420 allows single-transistor gain stages with >20 dB voltage gain in common-emitter topology. |
| TO-92 mechanical compatibility | Standard 3-lead through-hole footprint supports drop-in replacement in legacy BC-series PCB layouts. |
| Epitaxial silicon construction | Provides consistent fT and hFE across temperature, with TJ max = 150°C enabling operation in industrial enclosures. |
Applications
| Audio Preamp Stage | Sensor Signal Conditioning |
|---|---|
|
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Low-noise NPN amplifier in common-emitter configuration with emitter degeneration. Use Value: NF ≤ 3.0 dB preserves signal-to-noise ratio; hFE ≥ 420 enables >10× voltage gain with minimal external components. |
Use Scenario: Biasing and amplifying output from thermistors, photodiodes, or strain gauges in measurement bridges. IC Role / Device Role / Timing Role: Linear active element providing gain and impedance transformation in analog front-end circuits. Use Value: Stable hFE over temperature (±15% from −25°C to +85°C) ensures repeatable calibration; VCEO = 45 V accommodates wide supply rails. |
| DC Power Supply Regulation | General-Purpose Switching |
|
Use Scenario: Acting as pass transistor in linear voltage regulators or current-limiting circuits for 5–24 V outputs. IC Role / Device Role / Timing Role: Series-pass element controlled by error amplifier feedback loop. Use Value: PC = 500 mW supports up to 100 mA load at 5 V dropout; VCEO = 45 V allows use with unregulated 36 V inputs. |
Use Scenario: Driving LEDs, relays, or small solenoids in microcontroller I/O expansion boards. IC Role / Device Role / Timing Role: Saturated switch in common-emitter mode with base current limiting. Use Value: VCE(sat) ≤ 250 mV at IC = 10 mA reduces conduction loss; TO-92 mounting simplifies hand-soldered prototyping. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN low-noise amplification and switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC549CTA | Lower hFE (420–800 same class), identical NF (1.4–4.0 dB), but VCEO = 30 V vs. BC550ATA's 45 V. | Not suitable where collector swing exceeds 30 V; acceptable in low-voltage audio or sensor interfaces. | Select BC549CTA only if supply rails remain ≤ ±15 V and higher VCEO is unnecessary. |
| 2N3904TA | Higher VCEO = 40 V (vs. 45 V), lower hFE (100–300), NF = 5 dB typical - significantly noisier than BC550ATA. | Acceptable for digital switching or non-critical analog gain, but unsuitable for low-noise preamp roles. | Choose 2N3904TA when cost or availability outweighs noise and gain requirements; not a functional substitute in audio paths. |
Compared with BC549CTA and 2N3904TA, BC550ATA delivers superior noise performance and higher safe operating voltage, making it the preferred choice for precision analog amplification where VCEO > 30 V and NF < 3.0 dB are required.
Availability
BC550ATA is available at Aetrix Electronics and suitable for audio preamplifier design, sensor interface circuitry, and linear regulator implementation requiring stable component supply and long-term obsolescence management.
Supply support for BC550ATA 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 BC550ATA belongs to ON Semiconductor's legacy BC-series discrete transistor portfolio, designed for cost-sensitive, high-reliability analog and switching applications in through-hole assembly environments.
FAQ
What is the pin configuration of BC550ATA?
The BC550ATA 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 forward and leads pointing downward. This matches JEDEC TO-92 orientation and is identical across all BC546–BC550 variants. Confirm orientation using the marking dot or notch on the package body before soldering.
Does BC550ATA support audio frequency amplification?
Yes, BC550ATA is explicitly characterized for low-noise audio applications, with NF = 1.4–3.0 dB at 1 kHz and fT = 300 MHz. Its hFE stability and low Cob make it suitable for microphone preamplifiers, tone control stages, and line-level buffers where signal integrity is critical. Always verify biasing per actual circuit conditions using the datasheet's transfer curves.
What is the maximum collector current rating for BC550ATA?
The absolute maximum DC collector current for BC550ATA is 100 mA, as specified in the Absolute Maximum Ratings table. Continuous operation above 50 mA requires thermal derating per the datasheet's power dissipation curve, especially above 25°C ambient. For pulsed operation, peak IC must remain within SOA limits defined by VCE and time duration.
How does BC550ATA differ from BC547ATA?
BC550ATA offers higher VCEO (45 V vs. 45 V for BC547B/C but 65 V for BC546), identical hFE Class C range (420–800), and lower noise figure (1.4–3.0 dB vs. 2.0–10.0 dB for BC547). BC547ATA is optimized for general-purpose gain, while BC550ATA is tuned for low-noise linear operation - both share TO-92 packaging and pinout.
Is BC550ATA RoHS compliant and halogen-free?
Yes, BC550ATA manufactured by ON Semiconductor meets RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. The TO-92 package uses lead-free molding compound and matte tin-plated leads. Full compliance documentation, including test reports and declarations, is available upon request from Aetrix Electronics for qualified customers.
BC550ATA 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
BC550ATA FAQ
1.How can I place an order for BC550ATA through Aetrix?
Please submit a Request for Quotation (RFQ) for BC550ATA 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 BC550ATA reliable?
The price and inventory of BC550ATA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC550ATA is usually 5 days.
3.What payment methods are accepted for BC550ATA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC550ATA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC550ATA?
BC550ATA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC550ATA 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 BC550ATA?
For technical support, including BC550ATA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC550ATA requirements.
6.How does Aetrix verify that BC550ATA is sourced from the original manufacturer or authorized distributors?
All BC550ATA 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 BC550ATA meets industry standards.
7.What is the process for return or replacement of BC550ATA?
All BC550ATA units undergo pre-shipment inspection (PSI). If there is an issue with BC550ATA, 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 BC550ATA part is unused and in its original packaging.
Return procedure for BC550ATA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC550ATA Tags
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MMBT3906LT1G
onsemi
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MMBT3904-7-F
Diodes Incorporated
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onsemi
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MMBT3906-7-F
Diodes Incorporated
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MMBT3904-TP
Micro Commercial Co
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MMBT2222A-7-F
Diodes Incorporated
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BC846BLT1G
onsemi
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BC847B,215
Nexperia USA Inc.
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SMMBT3904LT1G
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MMBT2222A-TP
Micro Commercial Co
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onsemi
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