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onsemi BC550BTAR
- Part No.:
- BC550BTAR
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
BC550BTAR.pdf
- Description:
- TRANS NPN 45V 0.1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,104
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Product details
Overview
BC550BTAR 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, hFE = 200–450 (Class B), and fT = 300 MHz. It operates reliably at IC ≤ 100 mA and PC = 500 mW in TO-92 packaging, commonly used in audio preamplifiers and sensor interface stages.
For engineers reviewing the BC550BTAR datasheet, pinout, applications, or equivalent options, key selection criteria include its low noise figure (1.4–3.0 dB), tight hFE binning, VCEO rating, saturation voltage behavior under defined IB/IC conditions, and TO-92 mechanical compatibility in space-constrained PCB layouts.
Technical Context
This device belongs to the BC546–BC550 family of through-hole NPN transistors, sharing identical TO-92 package geometry and pinout (C-B-E) across variants. Its low-noise design targets small-signal amplification where NF ≤ 3.0 dB at IC = 200 μA, f = 1 kHz, RG = 2 kΩ - a specification explicitly assigned to BC550 in the datasheet.
It features a DC current gain range of 200–450 (Class B), collector-emitter saturation voltage of 90–250 mV at IC = 10 mA / IB = 0.5 mA, and output capacitance Cob = 3.5–6.0 pF at VCB = 10 V - parameters confirmed for BC550 in the "Electrical Characteristics" table.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 45 V - maximum safe collector-emitter voltage before breakdown; defines usable supply headroom in amplifier or switch stages. |
| hFE (Class B) | 200–450 - guaranteed DC current gain range at VCE = 5 V, IC = 2 mA; enables predictable biasing in linear amplifiers. |
| fT | 300 MHz - current gain bandwidth product at VCE = 5 V, IC = 10 mA; supports RF and wideband audio applications up to ~100 MHz. |
| NF | 1.4–3.0 dB - noise figure at VCE = 5 V, IC = 200 μA, f = 1 kHz, RG = 2 kΩ; critical for high-fidelity preamp and microphone circuits. |
| VCE(sat) | 90–250 mV - collector-emitter saturation voltage at IC = 10 mA / IB = 0.5 mA; determines conduction loss and thermal rise in switching use. |
| Cob | 3.5–6.0 pF - output capacitance at VCB = 10 V, f = 1 MHz; impacts high-frequency stability and Miller effect in common-emitter stages. |
Pinout & Package
BC550BTAR is housed in a standard JEDEC TO-92 3-lead plastic package with straight leads (bulk/ammo/tape-and-reel variants). Pin configuration is fixed: Lead 1 = Collector, Lead 2 = Base, Lead 3 = Emitter.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Collector) | Main current output terminal | Carries full load current; connects to supply rail or load in common-emitter configurations; requires thermal consideration at >50 mA. |
| 2 (Base) | Control input terminal | Accepts bias current to modulate collector current; high-impedance node requiring stable drive to maintain hFE linearity. |
| 3 (Emitter) | Current return path | Provides reference for VBE and emitter degeneration; often tied to ground or sense resistor in amplifier designs. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise amplification | Specified NF = 1.4–3.0 dB at 1 kHz enables high-SNR front-end stages in audio and instrumentation without added filtering. |
| Class B hFE binning | Guaranteed 200–450 gain range ensures consistent DC operating point setting across production lots in bias-critical circuits. |
| High fT bandwidth | 300 MHz fT supports stable operation beyond audio band into VHF, enabling use in oscillator and RF detector applications. |
| TO-92 mechanical standardization | JEDEC-compliant footprint allows direct replacement with BC547/BC548/BC549 and simplifies manual assembly and rework. |
Applications
| Audio Preamp Stage | Sensor Signal Amplifier |
|---|---|
|
Use Scenario: Low-level microphone or piezoelectric sensor signal conditioning prior to ADC sampling. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with emitter degeneration. Use Value: NF ≤ 3.0 dB and hFE ≥ 200 ensure minimal added noise and stable gain over temperature in battery-powered recorders. |
Use Scenario: Amplifying millivolt-level outputs from thermocouples or strain gauges in industrial monitoring systems. IC Role / Device Role / Timing Role: First-stage DC-coupled amplifier with precision bias network. Use Value: Tight hFE binning (200–450) and low VBE(on) variation (580–700 mV) reduce calibration drift across units. |
| General-Purpose Switch | Crystal Oscillator Buffer |
|
Use Scenario: Driving LEDs, relays, or logic inputs from microcontroller GPIO pins. IC Role / Device Role / Timing Role: Saturated switch with base current limiting resistor. Use Value: VCE(sat) ≤ 250 mV at IC = 10 mA minimizes power loss and self-heating during continuous on-state operation. |
Use Scenario: Isolating and buffering Pierce oscillator outputs in clock generation circuits. IC Role / Device Role / Timing Role: Low-capacitance emitter follower providing gain and drive strength. Use Value: Cob ≤ 6.0 pF prevents loading of crystal resonance and maintains frequency stability in 1–10 MHz oscillators. |
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 |
|---|---|---|---|
| BC549BTA | Same TO-92 package, same hFE Class B (200–450), but lower VCEO = 30 V and higher NF = 1.4–4.0 dB. | Not suitable for 40+ V supply rails; acceptable in low-voltage audio where tighter NF spec not required. | Select BC549BTA only when supply voltage ≤ 30 V and noise margin > 0.5 dB is acceptable. |
| 2N3904TA | TO-92 package, VCEO = 40 V, hFE = 100–300 (no class binning), NF not specified; fT = 300 MHz. | Lacks guaranteed low-noise performance and binned hFE; requires additional gain staging in precision analog designs. | Choose 2N3904TA for cost-sensitive digital switching where gain consistency and noise are secondary. |
Compared with BC549BTA and 2N3904TA, BC550BTAR uniquely delivers both 45 V VCEO headroom and factory-binned low-noise performance - making it the preferred choice for 3.3–48 V analog signal chains requiring repeatable gain and minimal SNR degradation.
Availability
BC550BTAR is available at Aetrix Electronics and suitable for audio preamplifiers, sensor interface modules, and general-purpose switching circuits requiring stable component supply, long-term manufacturability, and legacy through-hole compatibility.
Supply support for BC550BTAR 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 management, analog, sensors, and discrete devices for automotive, industrial, and consumer markets.
The BC550BTAR belongs to ON Semiconductor's legacy general-purpose transistor portfolio - designed for reliability, manufacturability, and broad compatibility in analog signal conditioning and switching applications.
FAQ
What is the pin configuration of BC550BTAR?
The BC550BTAR uses a standard TO-92 package with fixed pinout: Lead 1 is Collector, Lead 2 is Base, and Lead 3 is Emitter. This configuration is consistent across the BC546–BC550 family and verified in the Fairchild/ON Semiconductor datasheet Figure 7 and ordering table.
Does BC550BTAR have a specified noise figure?
Yes, BC550BTAR has a documented noise figure of 1.4–3.0 dB at VCE = 5 V, IC = 200 μA, f = 1 kHz, and RG = 2 kΩ. This value is explicitly assigned to the BC550 variant in the "Electrical Characteristics" table and distinguishes it from higher-noise variants like BC546/BC547.
What is the maximum collector current rating for BC550BTAR?
The absolute maximum collector current (IC) for BC550BTAR is 100 mA, as stated in the "Absolute Maximum Ratings" section of the datasheet. Continuous operation above this level risks thermal runaway or permanent junction damage, even with heatsinking.
Is BC550BTAR compatible with BC547 or BC549 in the same PCB footprint?
Yes, BC550BTAR shares identical TO-92 package dimensions and pinout (C-B-E) with BC547 and BC549, enabling direct physical replacement. However, electrical differences - including VCEO (45 V vs. 45 V vs. 30 V) and NF (1.4–3.0 dB vs. 2.0–10.0 dB) - require circuit validation before substitution.
What hFE classification does BC550BTAR belong to?
BC550BTAR is classified as Class B, with a guaranteed DC current gain (hFE) range of 200–450 at VCE = 5 V and IC = 2 mA. This binning is confirmed in the "hFE Classification" table and applies specifically to BC550, not BC546–BC549 variants.
BC550BTAR 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:
- 200 @ 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
BC550BTAR FAQ
1.How can I place an order for BC550BTAR through Aetrix?
Please submit a Request for Quotation (RFQ) for BC550BTAR 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 BC550BTAR reliable?
The price and inventory of BC550BTAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC550BTAR is usually 5 days.
3.What payment methods are accepted for BC550BTAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC550BTAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC550BTAR?
BC550BTAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC550BTAR 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 BC550BTAR?
For technical support, including BC550BTAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC550BTAR requirements.
6.How does Aetrix verify that BC550BTAR is sourced from the original manufacturer or authorized distributors?
All BC550BTAR 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 BC550BTAR meets industry standards.
7.What is the process for return or replacement of BC550BTAR?
All BC550BTAR units undergo pre-shipment inspection (PSI). If there is an issue with BC550BTAR, 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 BC550BTAR part is unused and in its original packaging.
Return procedure for BC550BTAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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