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

onsemi BCW72LT1

Name: BCW72LT1
Brand: onsemi
SKU: BCW72LT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BCW72LT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BCW72LT1.pdf

Description:: TRANS NPN 45V 0.1A SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BCW72LT1 from onsemi is an NPN silicon general-purpose transistor in SOT-23 package, rated for 45 V_CEO, 100 mA continuous collector current, and DC current gain (h_FE) of 200–450 at I_C = 2 mA, V_CE = 5 V. It serves as a low-power switching or amplification element in automotive signal conditioning, sensor interface circuits, and portable power management subsystems.

For engineers reviewing the BCW72LT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, noise performance at 1 kHz, SOT-23 terminal mapping, and AEC-Q101-qualified alternatives - all confirmed against onsemi's October 2024 Rev. 6 datasheet.

Technical Context

This NPN bipolar junction transistor operates with V_CEO = 45 V and V_CBO = 50 V, supporting reliable switching up to 300 MHz f_T under I_C = 10 mA, V_CE = 5 V conditions. Its low V_CE(sat) (0.21 V typical at I_C/I_B = 20) and V_BE(sat) (0.85 V typical at I_C/I_B = 20) enable efficient low-voltage drive in discrete logic-level interfaces.

Thermal design is constrained by R_JA = 556 °C/W on FR-5 board and 417 °C/W on alumina substrate, with 225 mW total dissipation at T_A = 25 °C (derated 1.8 mW/°C above). Noise figure is specified at 10 dB (I_C = 0.2 mA, V_CE = 5 V, R_S = 2 kΩ, BW = 200 Hz), confirming suitability for low-noise preamplifier stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 Vdc - Maximum safe collector-emitter voltage before breakdown; defines upper rail limit in switch-mode or amplifier bias networks.
I_C (continuous)	100 mAdc - Continuous collector current rating; sets maximum load-handling capacity in driver or buffer stages.
h_FE	200–450 - DC current gain range at I_C = 2 mA, V_CE = 5 V; determines base drive requirements for saturation in switching applications.
f_T	300 MHz - Current-gain bandwidth product; supports RF amplification up to ~100 MHz with usable gain margin.
V_CE(sat)	0.21 V (typ.) at I_C = 10 mA, I_B = 0.5 mA - Low saturation voltage minimizes conduction loss in digital output buffers and LED drivers.
C_obo	4.0 pF max - Output capacitance at V_CB = 10 V; impacts high-frequency response and stability in tuned amplifier designs.
NF	10 dB - Noise figure at 1 kHz, 0.2 mA collector current; enables use in audio preamp and sensor signal chain front-ends.

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm, with 1.90 mm lead pitch. Marking style 6 applies: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives forward-biased current to turn on transistor; requires current-limiting resistor in most digital interface applications.
2 (Emitter)	Current return path	Connected to ground or low-side reference; forms common-emitter configuration with defined emitter degeneration capability.
3 (Collector)	Output current sink	Drives load between supply rail and collector; supports active pull-down in level-shifting and open-collector logic interfaces.

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive temperature cycling, humidity, and mechanical stress per JESD47; suitable for under-hood sensor modules.
Pb-free, Halogen-free, RoHS compliant	Meets EU RoHS Directive 2011/65/EU and JEDEC JS709E; eliminates hazardous substances without compromising solderability or reliability.
Low noise figure (10 dB)	Enables use in microphone preamps and precision analog front-ends where signal-to-noise ratio below 1 kHz is critical.
High f_T (300 MHz)	Supports broadband amplification up to VHF band; maintains usable gain in RF detector and IF amplifier stages.
Low V_CE(sat) (0.21 V typ.)	Reduces power loss in battery-powered switches; extends runtime in portable medical and IoT endpoint devices.

Applications

Automotive Sensor Interface	Portable Audio Preamp
Use Scenario: Amplifying low-level signals from thermistor-based cabin temperature sensors in HVAC control units. IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration for stable DC bias. Use Value: 10 dB noise figure and 200–450 h_FE ensure accurate 12-bit ADC digitization of sub-mV sensor outputs across −40°C to +125°C.	Use Scenario: First-stage gain block in mono headphone amplifier for wearable health monitors. IC Role / Device Role / Timing Role: Low-noise, low-distortion NPN preamplifier operating at I_C = 0.2 mA, V_CE = 5 V. Use Value: 10 dB NF and 300 MHz f_T preserve audio fidelity up to 20 kHz while enabling compact PCB layout via SOT-23 footprint.
Industrial Digital I/O Buffer	LED Driver for Status Indication
Use Scenario: Level-shifting and current boosting for 3.3 V microcontroller GPIO driving 5 V industrial PLC input cards. IC Role / Device Role / Timing Role: Switching transistor in saturated common-emitter mode with forced β = 20. Use Value: 0.21 V V_CE(sat) limits power dissipation to <1 mW at 10 mA load, enabling fanless operation in DIN-rail mounted controllers.	Use Scenario: Constant-current sink for red/green status LEDs on network switch front panels. IC Role / Device Role / Timing Role: Low-side switch controlling LED anode-to-V_CC current path. Use Value: 100 mA I_C rating and 45 V V_CEO support multi-LED strings with series resistors up to 24 V supply rails.

Automotive Sensor Interface

Portable Audio Preamp

Use Scenario: Amplifying low-level signals from thermistor-based cabin temperature sensors in HVAC control units.

IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration for stable DC bias.

Use Value: 10 dB noise figure and 200–450 h_FE ensure accurate 12-bit ADC digitization of sub-mV sensor outputs across −40°C to +125°C.

Use Scenario: First-stage gain block in mono headphone amplifier for wearable health monitors.

IC Role / Device Role / Timing Role: Low-noise, low-distortion NPN preamplifier operating at I_C = 0.2 mA, V_CE = 5 V.

Use Value: 10 dB NF and 300 MHz f_T preserve audio fidelity up to 20 kHz while enabling compact PCB layout via SOT-23 footprint.

Industrial Digital I/O Buffer

LED Driver for Status Indication

Use Scenario: Level-shifting and current boosting for 3.3 V microcontroller GPIO driving 5 V industrial PLC input cards.

IC Role / Device Role / Timing Role: Switching transistor in saturated common-emitter mode with forced β = 20.

Use Value: 0.21 V V_CE(sat) limits power dissipation to <1 mW at 10 mA load, enabling fanless operation in DIN-rail mounted controllers.

Use Scenario: Constant-current sink for red/green status LEDs on network switch front panels.

IC Role / Device Role / Timing Role: Low-side switch controlling LED anode-to-V_CC current path.

Use Value: 100 mA I_C rating and 45 V V_CEO support multi-LED strings with series resistors up to 24 V supply rails.

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
BC846BTT1G	Higher h_FE (200–450 vs. 110–220), same SOT-23 package and V_CEO = 65 V; lower V_CE(sat) (0.15 V typ.) but higher C_ibo (12 pF).	Preferred for higher-gain linear amplification; less optimal for >100 MHz RF due to higher input capacitance.	Select BC846BTT1G when gain stability at low I_C (<1 mA) is prioritized over RF bandwidth.
MMBT3904LT1G	Identical pinout and V_CEO = 40 V; slightly lower h_FE (100–300), higher V_CE(sat) (0.2 V min), and no AEC-Q101 qualification.	Cost-optimized for consumer electronics; not approved for automotive-grade production.	Choose MMBT3904LT1G for non-automotive cost-sensitive designs where AEC-Q101 compliance is unnecessary.

Compared with BCW72LT1, BC846BTT1G offers higher gain and lower saturation voltage but trades off RF bandwidth due to increased input capacitance, while MMBT3904LT1G provides functional equivalence at lower cost but lacks automotive qualification and has reduced thermal robustness (R_JA = 625 °C/W).

Availability

BCW72LT1 is available at Aetrix Electronics and suitable for automotive sensor interfaces, portable audio preamplifiers, and industrial digital I/O buffers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BCW72LT1 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, and cloud infrastructure markets.

The BCW72LT1 belongs to onsemi's general-purpose bipolar transistor product line, engineered for high-reliability signal switching and amplification in harsh environments - particularly targeting AEC-Q101-compliant automotive subsystems and industrial control nodes.

FAQ

What is the maximum operating temperature range for BCW72LT1?

The BCW72LT1 has a junction and storage temperature range of −55°C to +150°C, validated per its AEC-Q101 qualification. This allows deployment in under-hood automotive modules and industrial equipment exposed to extreme ambient conditions. The device maintains specified electrical characteristics across this full range, with derated power dissipation above 25°C per the thermal resistance values in the datasheet.

Is BCW72LT1 pin-compatible with BC847 or MMBT3904?

No - BCW72LT1 uses Style 6 pinout (Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector), whereas BC847 variants commonly use Style 7 (Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector) and MMBT3904LT1G uses Style 6 only in select revisions. Physical pin mapping must be verified per each device's mechanical drawing; direct substitution without layout review risks incorrect biasing or circuit failure.

Does BCW72LT1 support high-frequency signal amplification?

Yes - BCW72LT1 achieves a current-gain bandwidth product (f_T) of 300 MHz at I_C = 10 mA, V_CE = 5 V, making it suitable for VHF-band amplification and RF detection up to ~100 MHz. Its 4.0 pF C_obo and 9.0 pF C_ibo support stable matching in tuned circuits, though layout parasitics must be minimized for optimal high-frequency performance.

What is the typical noise performance of BCW72LT1 in audio applications?

BCW72LT1 delivers a noise figure of 10 dB at I_C = 0.2 mA, V_CE = 5 V, R_S = 2 kΩ, and 1 kHz bandwidth. Its noise voltage (en) and noise current (in) curves confirm low 1/f noise contribution, enabling clean amplification of microvolt-level signals from electret microphones or piezoelectric sensors in battery-powered audio endpoints.

How does the thermal performance of BCW72LT1 compare between FR-5 and alumina substrates?

On FR-5 board, BCW72LT1 exhibits R_JA = 556 °C/W and 225 mW dissipation at 25°C (derated 1.8 mW/°C); on alumina substrate, R_JA improves to 417 °C/W with 300 mW dissipation (derated 2.4 mW/°C). This 25% lower thermal resistance on alumina enables 33% higher power handling in thermally constrained space-constrained modules like automotive radar front-ends.

BCW72LT1 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):: 100 mA

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

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 500µA, 10mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 2mA, 5V

Power - Max:: 300 mW

Frequency - Transition:: 300MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

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

BCW72LT1 FAQ

1.How can I place an order for BCW72LT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BCW72LT1 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 BCW72LT1 reliable?

The price and inventory of BCW72LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCW72LT1 is usually 5 days.

3.What payment methods are accepted for BCW72LT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCW72LT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCW72LT1?

BCW72LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCW72LT1 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 BCW72LT1?

For technical support, including BCW72LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCW72LT1 requirements.

6.How does Aetrix verify that BCW72LT1 is sourced from the original manufacturer or authorized distributors?

All BCW72LT1 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 BCW72LT1 meets industry standards.

7.What is the process for return or replacement of BCW72LT1?

All BCW72LT1 units undergo pre-shipment inspection (PSI). If there is an issue with BCW72LT1, 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 BCW72LT1 part is unused and in its original packaging.

Return procedure for BCW72LT1:

1.Submit a request within 90 days.

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

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