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

onsemi BC337-040G

Name: BC337-040G
Brand: onsemi
SKU: BC337-040G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC337-040G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC337-040G.pdf

Description:: TRANS NPN 45V 0.8A TO92

Quantity:: RFQ Add To RFQ list

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Inventory:3,497

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Product details

Overview

BC337-040G from onsemi is an NPN general-purpose bipolar junction transistor (BJT) in TO-92 package, rated for 45 V V_CEO, 500 mA I_C, and 625 mW P_D, with DC current gain (h_FE) of 250–630 at I_C = 10 mA and V_CE = 1 V. It serves as a low-voltage switching or linear amplification device in discrete logic interfaces and signal conditioning circuits.

For engineers reviewing the BC337-040G datasheet, pinout, applications, or equivalent options, key selection considerations include its guaranteed h_FE range, TO-92 mechanical compatibility, thermal derating behavior above 25°C, and saturation voltage under defined drive conditions.

Technical Context

The BC337-040G implements a planar epitaxial silicon NPN structure optimized for medium-current switching and analog amplification. Its h_FE binning ('040' suffix) specifies 250–630 at 10 mA/1 V, distinguishing it from lower-gain variants like BC337-16 or BC337-25.

It features a maximum collector-emitter saturation voltage (V_CE(sat)) of 0.7 V at I_C = 100 mA and I_B = 5 mA, supporting efficient low-side switch operation. Junction-to-ambient thermal resistance (R_θJA) is 200°C/W in free air, requiring board-level thermal management for sustained >300 mA operation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum allowable collector-emitter voltage before breakdown; sets upper rail limit for low-voltage DC circuits.
I_C max	500 mA - Continuous collector current rating; defines safe operating area for switching loads up to ~200 mA with margin.
P_D	625 mW - Total power dissipation at 25°C ambient; derates linearly above 25°C per R_θJA = 200°C/W.
h_FE @ 10 mA / 1 V	250–630 - Guaranteed DC current gain range; enables predictable base drive sizing for saturated switching.
V_CE(sat) @ 100 mA / 5 mA	≤0.7 V - Low saturation voltage ensures minimal conduction loss in digital output stages and relay drivers.
f_T	100 MHz - Transition frequency; supports small-signal amplification up to ~10 MHz with usable gain.

Pinout & Package

BC337-040G is housed in a standard TO-92 plastic package with 3 leads, designed for through-hole mounting and manual prototyping. Lead spacing is 0.4 inch (10.16 mm), body diameter 3.2 mm, and total length 4.6 mm.

Pin/Terminal	Circuit Role	Design Meaning
E (Emitter)	Current sink terminal	Connected to ground or low-side reference; base-emitter junction forward-biased to enable conduction.
B (Base)	Control input	Receives current-limited drive (typically 1–10 mA); controls collector current via h_FE-scaled relationship.
C (Collector)	Current source terminal	Connected to load and supply rail; delivers amplified current to external circuitry when B-E junction is biased.

Key Features

Feature	Design Value
High h_FE binning (040)	Guaranteed 250–630 gain enables stable biasing without feedback networks in simple amplifier or switch designs.
Low V_CE(sat)	≤0.7 V at 100 mA/5 mA reduces power loss and heat generation in saturated switching applications.
TO-92 mechanical standardization	Ensures drop-in replacement across legacy designs using BC337, BC547, or PN2222A footprints.
Qualified per AEC-Q101	Meets automotive-grade reliability requirements for temperature cycling, humidity, and mechanical shock testing.

Applications

LED Driver Circuit	Microcontroller GPIO Interface
Use Scenario: Driving 20 mA indicator LEDs from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: NPN switch providing current amplification and level translation between logic-level signals and LED loads. Use Value: Enables direct control of LEDs without exceeding MCU I/O current limits, leveraging BC337-040G's 250–630 h_FE to reduce base drive burden.	Use Scenario: Isolating and buffering digital signals between mixed-voltage subsystems (e.g., 3.3 V MCU to 5 V peripheral). IC Role / Device Role / Timing Role: Discrete level shifter and noise-immune signal conditioner using common-emitter configuration. Use Value: Provides galvanic isolation and gain margin against capacitive loading, supported by BC337-040G's 100 MHz f_T and low V_CE(sat).
Relay Coil Driver	Audio Pre-amplifier Stage
Use Scenario: Switching 12 V, 100 mA relay coils in industrial control panels. IC Role / Device Role / Timing Role: Low-side switch controlling coil current path to ground. Use Value: BC337-040G's ≤0.7 V V_CE(sat) minimizes coil voltage drop and ensures reliable relay pull-in under marginal supply conditions.	Use Scenario: Amplifying line-level audio signals (≤1 V_pp) in battery-powered portable devices. IC Role / Device Role / Timing Role: Single-stage common-emitter small-signal amplifier with emitter degeneration. Use Value: BC337-040G's 250–630 h_FE and 100 MHz f_T support stable mid-band gain (20–20 kHz) with low distortion at low quiescent current.

LED Driver Circuit

Microcontroller GPIO Interface

Use Scenario: Driving 20 mA indicator LEDs from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: NPN switch providing current amplification and level translation between logic-level signals and LED loads.

Use Value: Enables direct control of LEDs without exceeding MCU I/O current limits, leveraging BC337-040G's 250–630 h_FE to reduce base drive burden.

Use Scenario: Isolating and buffering digital signals between mixed-voltage subsystems (e.g., 3.3 V MCU to 5 V peripheral).

IC Role / Device Role / Timing Role: Discrete level shifter and noise-immune signal conditioner using common-emitter configuration.

Use Value: Provides galvanic isolation and gain margin against capacitive loading, supported by BC337-040G's 100 MHz f_T and low V_CE(sat).

Relay Coil Driver

Audio Pre-amplifier Stage

Use Scenario: Switching 12 V, 100 mA relay coils in industrial control panels.

IC Role / Device Role / Timing Role: Low-side switch controlling coil current path to ground.

Use Value: BC337-040G's ≤0.7 V V_CE(sat) minimizes coil voltage drop and ensures reliable relay pull-in under marginal supply conditions.

Use Scenario: Amplifying line-level audio signals (≤1 V_pp) in battery-powered portable devices.

IC Role / Device Role / Timing Role: Single-stage common-emitter small-signal amplifier with emitter degeneration.

Use Value: BC337-040G's 250–630 h_FE and 100 MHz f_T support stable mid-band gain (20–20 kHz) with low distortion at low quiescent current.

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
BC337-25G	Lower h_FE range (160–400); otherwise identical electrical and mechanical specs.	Suitable where tighter base drive control is needed or gain variability must be minimized.	Select BC337-25G if design requires conservative h_FE margin or operates near V_CE(sat) limits at high I_C.
PN2222A	h_FE range 100–300; higher V_CE(sat) (≤1.2 V at 150 mA/15 mA); same TO-92 package.	Preferred in cost-sensitive, non-critical switching where gain tolerance is less critical.	Choose PN2222A only when BC337-040G's higher gain and lower saturation voltage are not required.

Compared with BC337-040G, BC337-25G offers reduced gain spread for more predictable biasing, while PN2222A trades gain and saturation performance for broader legacy availability-neither is pin-compatible without verifying layout clearance for thermal pad variants.

Availability

BC337-040G is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface modules, relay coil drivers, and audio pre-amplifier stages requiring stable component supply and consistent h_FE binning.

Supply support for BC337-040G 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, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC337 series belongs to onsemi's general-purpose bipolar transistor product line, engineered for robustness, consistency, and ease of use in discrete analog and digital interface designs across consumer and industrial markets.

FAQ

What is the guaranteed h_FE range for BC337-040G?

The BC337-040G 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 '040' suffix denotes the highest-gain bin within the BC337 family, enabling reliable base drive calculation in switching and amplification circuits using BC337-040G.

Is BC337-040G suitable for automotive applications?

Yes, BC337-040G is qualified to AEC-Q101 standards, confirming its suitability for automotive applications including body control modules, lighting interfaces, and sensor signal conditioning. Its tested performance across temperature, humidity, and mechanical stress validates BC337-040G for under-hood and cabin environments.

What is the maximum power dissipation of BC337-040G at 70°C ambient?

At 70°C ambient, BC337-040G's maximum power dissipation is derated to 375 mW, calculated using its 625 mW rating at 25°C and R_θJA = 200°C/W. This thermal limit must be observed in PCB layouts lacking copper pour or forced airflow to prevent junction overheating in BC337-040G.

Can BC337-040G replace BC337-25G in an existing design?

BC337-040G can replace BC337-25G mechanically and electrically, but its higher h_FE (250–630 vs. 160–400) may increase collector current or cause overdrive in base-resistor-biased circuits. Verify bias stability and saturation margin when substituting BC337-040G for BC337-25G in production hardware.

What is the typical V_CE(sat) of BC337-040G under switching conditions?

The typical V_CE(sat) of BC337-040G is 0.2 V at I_C = 10 mA and I_B = 0.5 mA, and remains ≤0.7 V at I_C = 100 mA and I_B = 5 mA. These values define conduction loss in BC337-040G-based low-side switches used in LED and relay driver applications.

BC337-040G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

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)

BC337-040G FAQ

1.How can I place an order for BC337-040G through Aetrix?

Please submit a Request for Quotation (RFQ) for BC337-040G 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 BC337-040G reliable?

The price and inventory of BC337-040G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC337-040G is usually 5 days.

3.What payment methods are accepted for BC337-040G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC337-040G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC337-040G?

BC337-040G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC337-040G 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 BC337-040G?

For technical support, including BC337-040G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC337-040G requirements.

6.How does Aetrix verify that BC337-040G is sourced from the original manufacturer or authorized distributors?

All BC337-040G 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 BC337-040G meets industry standards.

7.What is the process for return or replacement of BC337-040G?

All BC337-040G units undergo pre-shipment inspection (PSI). If there is an issue with BC337-040G, 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 BC337-040G part is unused and in its original packaging.

Return procedure for BC337-040G:

1.Submit a request within 90 days.

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

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