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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi BCW66GLT1

Name: BCW66GLT1
Brand: onsemi
SKU: BCW66GLT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BCW66GLT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BCW66GLT1.pdf

Description:: TRANS NPN 45V 0.8A SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BCW66GLT1 from onsemi is an NPN silicon general-purpose transistor in SOT-23 package, rated for 45 V_CEO, 800 mA continuous collector current, and 100 MHz f_T, commonly used in low-power switching and linear amplification stages of consumer audio and signal conditioning circuits.

For engineers reviewing the BCW66GLT1 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO/I_C derating at elevated temperature, h_FE variation across operating current, saturation voltage at defined I_B/I_C ratios, and thermal resistance on FR-5 versus alumina substrates.

Technical Context

This discrete NPN bipolar junction transistor operates in active, saturation, and cutoff regions with verified DC current gain (h_FE) ranging from 50 to 400 depending on I_C (10 mA to 500 mA) and V_CE (1.0–10 V). Its 100 MHz f_T supports small-signal amplification up to VHF band edges under specified bias conditions.

Switching performance is characterized by 100 ns turn-on and 400 ns turn-off times into a 150 Ω load with 15 mA base drive; C_ibo = 80 pF and C_obo = 12 pF define high-frequency input/output capacitance limits at 1 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage before breakdown under open-base condition with I_C = 10 mA.
I_C (continuous)	800 mA - Absolute maximum DC collector current; derated above 25°C per 1.8 mW/°C on FR-5 board.
f_T	100 MHz - Current-gain bandwidth product at I_C = 20 mA, V_CE = 10 V, defining usable small-signal amplification limit.
h_FE (min–max)	50–400 - DC current gain range across I_C = 10 mA to 500 mA, critical for bias stability in amplifier designs.
V_CE(sat)	0.3–0.7 V - Saturation voltage at I_C = 100–500 mA with corresponding I_B, directly impacting conduction loss in switch applications.
R_JA (FR-5)	556 °C/W - Junction-to-ambient thermal resistance on standard FR-5 PCB, determining max power dissipation at given ambient temperature.

Pinout & Package

SOT-23 (TO-236) plastic surface-mount package, 3-pin, case 318-08, 2.0 mm × 0.95 mm footprint, 0.9 mm height, lead finish Pb-free (RoHS compliant).

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for forward-biased junction; requires current-limited drive to achieve target I_C and avoid thermal runaway.
2	Emiter	Common reference node in common-emitter configuration; connected to ground or low-impedance return path.
3	Collector	Output current sink node; carries full load current and dissipates power as I_C × V_CE during conduction.

Key Features

Feature	Design Value
Pb-free SOT-23 package	Complies with RoHS Directive 2011/65/EU; compatible with lead-free reflow profiles (J-STD-020).
High f_T (100 MHz)	Enables stable small-signal amplification in audio preamp and RF detector front-ends up to 30 MHz practical bandwidth.
Wide h_FE range (50–400)	Supports both high-gain low-current biasing (e.g., sensor interface) and robust medium-current switching (e.g., LED driver).
Low V_CE(sat) (0.3 V min)	Reduces conduction loss in battery-powered switch applications, improving efficiency in portable device power control.

Applications

Audio Signal Amplifier	LED Driver Switch
Use Scenario: Low-noise preamplification stage in portable microphone or line-level audio circuits. IC Role / Device Role / Timing Role: NPN BJT configured in common-emitter topology for voltage gain with 10–100 kHz bandwidth. Use Value: 10 dB noise figure at 1 kHz enables clean signal amplification without significant SNR degradation.	Use Scenario: On/off control of indicator or status LEDs in industrial HMI panels. IC Role / Device Role / Timing Role: Medium-current saturated switch driving up to 500 mA LED strings from microcontroller GPIO. Use Value: V_CE(sat) ≤ 0.7 V at I_C = 500 mA ensures < 350 mW dissipation, avoiding thermal shutdown in compact enclosures.
DC-DC Converter Feedback	Signal Level Shifter
Use Scenario: Error amplifier input stage in isolated flyback converter feedback loop. IC Role / Device Role / Timing Role: Linear-mode transistor amplifying optocoupler output current to regulate primary-side PWM duty cycle. Use Value: h_FE ≥ 110 at I_C = 10 mA provides stable transconductance for precise regulation under varying load conditions.	Use Scenario: Bidirectional logic level translation between 3.3 V MCU and 5 V peripheral bus. IC Role / Device Role / Timing Role: Emitter-follower configured BJT enabling low-latency, rail-to-rail voltage translation without external bias resistors. Use Value: C_ibo = 80 pF and f_T = 100 MHz support rise/fall times < 5 ns for 1 Mbps digital signals.

Audio Signal Amplifier

LED Driver Switch

Use Scenario: Low-noise preamplification stage in portable microphone or line-level audio circuits.

IC Role / Device Role / Timing Role: NPN BJT configured in common-emitter topology for voltage gain with 10–100 kHz bandwidth.

Use Value: 10 dB noise figure at 1 kHz enables clean signal amplification without significant SNR degradation.

Use Scenario: On/off control of indicator or status LEDs in industrial HMI panels.

IC Role / Device Role / Timing Role: Medium-current saturated switch driving up to 500 mA LED strings from microcontroller GPIO.

Use Value: V_CE(sat) ≤ 0.7 V at I_C = 500 mA ensures < 350 mW dissipation, avoiding thermal shutdown in compact enclosures.

DC-DC Converter Feedback

Signal Level Shifter

Use Scenario: Error amplifier input stage in isolated flyback converter feedback loop.

IC Role / Device Role / Timing Role: Linear-mode transistor amplifying optocoupler output current to regulate primary-side PWM duty cycle.

Use Value: h_FE ≥ 110 at I_C = 10 mA provides stable transconductance for precise regulation under varying load conditions.

Use Scenario: Bidirectional logic level translation between 3.3 V MCU and 5 V peripheral bus.

IC Role / Device Role / Timing Role: Emitter-follower configured BJT enabling low-latency, rail-to-rail voltage translation without external bias resistors.

Use Value: C_ibo = 80 pF and f_T = 100 MHz support rise/fall times < 5 ns for 1 Mbps digital signals.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC847BLT1G	Lower I_C (100 mA), higher h_FE (200–450), same SOT-23 package.	Better suited for low-current amplification; not recommended for >200 mA switching loads.	Select when bias stability at µA–mA levels is prioritized over power handling.
MMBT3904LT1G	Same V_CEO (40 V), lower I_C (200 mA), higher f_T (300 MHz), same SOT-23.	Optimized for high-speed digital switching and RF detection; limited thermal margin for sustained 500 mA operation.	Prefer for fast edge-rate logic interfacing where speed outweighs current capacity.

Compared with BCW66GLT1, BC847BLT1G trades current capability for tighter h_FE distribution at low I_C, while MMBT3904LT1G sacrifices thermal robustness for higher frequency response-neither is pin-compatible nor drop-in; layout review required for substitution.

Availability

BCW66GLT1 is available at Aetrix Electronics and suitable for audio signal amplification, LED driver switching, DC-DC converter feedback, and signal level shifting requiring stable component supply and RoHS-compliant packaging.

Supply support for BCW66GLT1 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BCW66GLT1 belongs to onsemi's general-purpose bipolar transistor product line, designed for cost-sensitive, medium-current linear and switching applications in space-constrained PCB layouts.

FAQ

What is the maximum continuous collector current rating for BCW66GLT1?

The BCW66GLT1 has a maximum continuous collector current (I_C) rating of 800 mA at T_A = 25°C on FR-5 board. This rating must be derated by 1.8 mW/°C above 25°C ambient, limiting usable current in high-temperature environments. The BCW66GLT1 datasheet specifies this value under defined thermal test conditions and should be validated against actual board layout and airflow.

Does BCW66GLT1 support lead-free soldering processes?

Yes, BCW66GLT1 is offered in a Pb-free SOT-23 package compliant with RoHS Directive 2011/65/EU. It is qualified for standard lead-free reflow profiles per J-STD-020, with peak temperatures up to 260°C. The BCW66GLT1 marking "G" suffix (e.g., BCW66GLT1G) explicitly denotes the Pb-free variant, though BCW66GLT1 itself is also Pb-free per onsemi documentation.

What is the typical noise figure of BCW66GLT1 and under what conditions is it measured?

The BCW66GLT1 exhibits a typical noise figure (NF) of 10 dB, measured at V_CE = 5.0 V, I_C = 0.2 mA, source resistance R_S = 1.0 kΩ, frequency f = 1.0 kHz, and bandwidth BW = 200 Hz. This value reflects its suitability for low-noise preamplifier stages; the BCW66GLT1 noise performance degrades at higher currents or frequencies outside this test condition.

Can BCW66GLT1 be used in switching applications with 500 mA load current?

Yes, BCW66GLT1 is rated for 800 mA continuous collector current and supports 500 mA switching loads when properly biased into saturation (e.g., I_B ≥ 50 mA for I_C = 500 mA). Its V_CE(sat) ≤ 0.7 V at that condition ensures acceptable conduction loss. Thermal design must account for R_JA = 556 °C/W on FR-5 to avoid junction overheating in BCW66GLT1-based switch circuits.

What are the pin assignments for BCW66GLT1 in the SOT-23 package?

The BCW66GLT1 uses standard SOT-23 pinout: Pin 1 is Base, Pin 2 is Emitter, Pin 3 is Collector. This assignment is confirmed in the official onsemi datasheet (BCW66GLT1/D, Rev. 0, Feb 2005), marked on the device body as "EG" with orientation matching JEDEC TO-236 outline. Correct pin identification is essential to avoid reverse-bias damage during BCW66GLT1 circuit integration.

BCW66GLT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 800 mA

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 700mV @ 50mA, 500mA

Current - Collector Cutoff (Max):: 20nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 160 @ 100mA, 1V

Power - Max:: 300 mW

Frequency - Transition:: 100MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

BCW66GLT1 FAQ

1.How can I place an order for BCW66GLT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BCW66GLT1 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 BCW66GLT1 reliable?

The price and inventory of BCW66GLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCW66GLT1 is usually 5 days.

3.What payment methods are accepted for BCW66GLT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCW66GLT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCW66GLT1?

BCW66GLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCW66GLT1 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 BCW66GLT1?

For technical support, including BCW66GLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCW66GLT1 requirements.

6.How does Aetrix verify that BCW66GLT1 is sourced from the original manufacturer or authorized distributors?

All BCW66GLT1 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 BCW66GLT1 meets industry standards.

7.What is the process for return or replacement of BCW66GLT1?

All BCW66GLT1 units undergo pre-shipment inspection (PSI). If there is an issue with BCW66GLT1, 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 BCW66GLT1 part is unused and in its original packaging.

Return procedure for BCW66GLT1:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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