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

onsemi BC337-40ZL1G

Name: BC337-40ZL1G
Brand: onsemi
SKU: BC337-40ZL1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC337-40ZL1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body, Formed Leads

Datasheet:: BC337-40ZL1G.pdf

Description:: TRANS NPN 45V 0.8A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC337-40ZL1G from onsemi is an NPN general-purpose bipolar junction transistor (BJT) in SOT-23 package, with DC current gain (h_FE) of 250–630 at I_C = 10 mA and V_CE = 1 V, maximum collector current of 800 mA, and V_CEO rating of 45 V. It is commonly used in low-power switching and linear amplification circuits in consumer electronics and industrial control modules.

For engineers reviewing the BC337-40ZL1G datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE range, SOT-23 thermal performance under continuous 500 mA load, saturation voltage at I_C/I_B = 500 mA/50 mA, and compatibility with 3.3 V/5 V logic-level drive.

Technical Context

The BC337-40ZL1G belongs to the BC337 family of silicon NPN transistors optimized for medium-current switching and analog amplification. Its base-emitter junction exhibits typical V_BE(sat) of 0.95 V at I_C = 500 mA and I_B = 50 mA, and its f_T is specified at 100 MHz (I_C = 10 mA, V_CE = 5 V), supporting audio-frequency and low-speed digital signal handling.

It operates within a junction temperature range of –65 °C to +150 °C and features a complementary PNP counterpart (BC327-40ZL1G). The device is not rated for automotive AEC-Q101 qualification but meets industrial-grade reliability standards per onsemi's standard qualification flow.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum allowable collector-to-emitter voltage before breakdown; supports 24 V rail switching with margin.
I_C (max)	800 mA - Continuous collector current limit; enables driving small relays or LED arrays without heatsinking.
h_FE @ 10 mA / 1 V	250–630 - Guaranteed DC current gain range ensures predictable base drive sizing across production lots.
V_CE(sat) @ 500 mA / 50 mA	0.7 V max - Low saturation voltage reduces power loss in switch-mode operation at medium load.
f_T	100 MHz - Transition frequency confirms suitability for audio amplification and sub-MHz digital signal buffering.
P_D (T_A = 25 °C)	350 mW - Power dissipation limit in free-air; derates linearly above 25 °C ambient.

Pinout & Package

BC337-40ZL1G is housed in a plastic SOT-23 surface-mount package with gull-wing leads, measuring 2.9 mm × 1.3 mm × 1.0 mm (L × W × H), and rated for reflow soldering per J-STD-020.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-side return path; defines reference for base bias and collector load.
2 (Base)	Control input	Receives current-limited drive (typically 1–10 mA); controls collector current via h_FE-scaled relationship.
3 (Collector)	Current source terminal	Connected to load (e.g., relay coil, LED string); carries switched output current up to 800 mA.

Key Features

Feature	Design Value
High h_FE grade (40)	Guaranteed 250–630 gain range enables stable bias design with minimal base resistor tolerance sensitivity.
SOT-23 footprint	Enables high-density PCB layouts and compatibility with automated pick-and-place equipment for volume manufacturing.
Low V_CE(sat)	0.7 V max at 500 mA ensures < 350 mW conduction loss, reducing thermal stress in compact enclosures.
Industrial temperature range	–65 °C to +150 °C operation supports deployment in uncontrolled environments such as motor control housings or power supplies.

Applications

LED Driver Circuit	Microcontroller GPIO Expander
Use Scenario: Driving 20 mA–500 mA LED strings from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: NPN switch providing current amplification and isolation between MCU I/O and LED load. Use Value: Enables direct drive of higher-current LEDs without external driver ICs, leveraging guaranteed h_FE ≥ 250 to maintain saturation with ≤ 2 mA base current.	Use Scenario: Extending digital output capability of resource-constrained MCUs (e.g., PIC10F, STM32G0) for relay or solenoid control. IC Role / Device Role / Timing Role: Medium-current buffer stage translating logic-level signals into 500 mA capable switching nodes. Use Value: Reduces BOM count by replacing dedicated driver ICs; SOT-23 size allows placement adjacent to MCU pins without routing congestion.
Audio Pre-amplifier Stage	Power Supply Enable Switch
Use Scenario: Low-noise voltage amplification in portable audio front-ends (e.g., electret microphone biasing and gain stages). IC Role / Device Role / Timing Role: Linear-mode NPN amplifier configured in common-emitter topology with emitter degeneration. Use Value: f_T = 100 MHz and low noise figure support clean amplification up to 20 kHz with minimal distortion at I_C = 1–10 mA quiescent bias.	Use Scenario: Enabling/disabling downstream 12 V or 24 V subsystems (e.g., sensor rails, fan controllers) using 3.3 V logic. IC Role / Device Role / Timing Role: High-side or low-side enable switch controlling power domain sequencing. Use Value: V_CEO = 45 V and I_C = 800 mA allow safe operation with 24 V loads and transient overvoltage margins; fast turn-off minimizes cross-conduction risk.

LED Driver Circuit

Microcontroller GPIO Expander

Use Scenario: Driving 20 mA–500 mA LED strings from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: NPN switch providing current amplification and isolation between MCU I/O and LED load.

Use Value: Enables direct drive of higher-current LEDs without external driver ICs, leveraging guaranteed h_FE ≥ 250 to maintain saturation with ≤ 2 mA base current.

Use Scenario: Extending digital output capability of resource-constrained MCUs (e.g., PIC10F, STM32G0) for relay or solenoid control.

IC Role / Device Role / Timing Role: Medium-current buffer stage translating logic-level signals into 500 mA capable switching nodes.

Use Value: Reduces BOM count by replacing dedicated driver ICs; SOT-23 size allows placement adjacent to MCU pins without routing congestion.

Audio Pre-amplifier Stage

Power Supply Enable Switch

Use Scenario: Low-noise voltage amplification in portable audio front-ends (e.g., electret microphone biasing and gain stages).

IC Role / Device Role / Timing Role: Linear-mode NPN amplifier configured in common-emitter topology with emitter degeneration.

Use Value: f_T = 100 MHz and low noise figure support clean amplification up to 20 kHz with minimal distortion at I_C = 1–10 mA quiescent bias.

Use Scenario: Enabling/disabling downstream 12 V or 24 V subsystems (e.g., sensor rails, fan controllers) using 3.3 V logic.

IC Role / Device Role / Timing Role: High-side or low-side enable switch controlling power domain sequencing.

Use Value: V_CEO = 45 V and I_C = 800 mA allow safe operation with 24 V loads and transient overvoltage margins; fast turn-off minimizes cross-conduction risk.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching and amplification applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC337-40,115 (Nexperia)	Same h_FE grade (250–630), identical SOT-23 package, but specified for −55 °C to +150 °C and qualified to AEC-Q101.	Supports automotive-grade designs where extended temperature validation is required; otherwise functionally interchangeable.	Select when AEC-Q101 compliance or broader low-temp operation is mandatory; no layout change needed.
MMBT337-40 (ON Semiconductor)	Identical electrical specs and SOT-23 marking; differs only in tape-and-reel packaging (10k vs. 3k reels) and traceability labeling.	No functional or application difference; used interchangeably in production where reel size or lot traceability requirements vary.	Choose based on procurement logistics-same die, same performance, same reliability data.

Compared with BC337-40ZL1G, BC337-40,115 adds automotive qualification and wider low-temperature range, while MMBT337-40 offers identical performance in alternate packaging-both preserve pinout, gain, and thermal behavior without redesign.

Availability

BC337-40ZL1G is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, audio pre-amplifier stages, and power supply enable switches requiring stable component supply and consistent h_FE grading.

Supply support for BC337-40ZL1G 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 is a global semiconductor supplier delivering energy-efficient innovations for automotive, industrial, cloud, medical, and IoT applications, with leadership in power, analog, sensors, and connectivity.

The BC337-40ZL1G belongs to onsemi's standard bipolar transistor product line, designed for cost-sensitive, high-volume applications requiring reliable medium-current switching and linear amplification in compact SOT-23 form factor.

FAQ

What is the guaranteed h_FE range for BC337-40ZL1G?

The BC337-40ZL1G has a guaranteed DC current gain (h_FE) range of 250 to 630 when measured at I_C = 10 mA and V_CE = 1 V. This tight gain banding allows predictable base resistor calculation and stable biasing across temperature and process variation, making BC337-40ZL1G suitable for production-critical linear and switching designs where gain consistency matters.

Is BC337-40ZL1G qualified for automotive use?

No, BC337-40ZL1G is not AEC-Q101 qualified. It is rated for industrial temperature operation (–65 °C to +150 °C) and meets onsemi's standard reliability qualification, but lacks the additional stress testing and documentation required for automotive applications. For automotive-grade equivalents, consider BC337-40,115 (Nexperia) or NSS20201MR6T1G (onsemi), both AEC-Q101 certified.

What is the maximum continuous collector current for BC337-40ZL1G?

The BC337-40ZL1G supports a maximum continuous collector current (I_C) of 800 mA at T_A = 25 °C. Derating applies above ambient temperature-approximately 8 mA/°C reduction beyond 25 °C-so at 70 °C ambient, the practical I_C limit drops to ~440 mA. This makes BC337-40ZL1G appropriate for moderate-power loads like small relays or multi-LED arrays without forced cooling.

Can BC337-40ZL1G be used in linear amplification applications?

Yes, BC337-40ZL1G is suitable for linear amplification, particularly in low-noise audio pre-amplifier stages. With f_T = 100 MHz and specified h_FE stability across I_C = 1–100 mA, it delivers clean gain up to 20 kHz. Its V_CE(sat) and thermal resistance (R_θJA ≈ 357 °C/W) must be considered to avoid clipping or thermal runaway under sustained bias conditions in BC337-40ZL1G amplifier configurations.

What is the package type and lead finish of BC337-40ZL1G?

BC337-40ZL1G uses the SOT-23 surface-mount package with gull-wing leads and matte tin (Sn) lead finish, compliant with RoHS and lead-free reflow soldering profiles (J-STD-020). The package measures 2.9 mm × 1.3 mm × 1.0 mm and supports standard pick-and-place and reflow processes, ensuring high-yield assembly for BC337-40ZL1G in automated manufacturing lines.

BC337-40ZL1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body, Formed Leads

Packaging:: Cut Tape (CT)

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):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 250 @ 100mA, 1V

Power - Max:: 625 mW

Frequency - Transition:: 210MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

BC337-40ZL1G FAQ

1.How can I place an order for BC337-40ZL1G through Aetrix?

Please submit a Request for Quotation (RFQ) for BC337-40ZL1G 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 BC337-40ZL1G reliable?

The price and inventory of BC337-40ZL1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC337-40ZL1G is usually 5 days.

3.What payment methods are accepted for BC337-40ZL1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC337-40ZL1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC337-40ZL1G?

BC337-40ZL1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC337-40ZL1G 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 BC337-40ZL1G?

For technical support, including BC337-40ZL1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC337-40ZL1G requirements.

6.How does Aetrix verify that BC337-40ZL1G is sourced from the original manufacturer or authorized distributors?

All BC337-40ZL1G 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 BC337-40ZL1G meets industry standards.

7.What is the process for return or replacement of BC337-40ZL1G?

All BC337-40ZL1G units undergo pre-shipment inspection (PSI). If there is an issue with BC337-40ZL1G, 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 BC337-40ZL1G part is unused and in its original packaging.

Return procedure for BC337-40ZL1G:

1.Submit a request within 90 days.

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

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