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

onsemi BD37910STU

Name: BD37910STU
Brand: onsemi
SKU: BD37910STU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD37910STU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: BD37910STU.pdf

Description:: TRANS NPN 80V 2A TO-126-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BD37910STU from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for medium-power linear amplification and switching applications, with V_CEO = 80 V, I_C = 2 A DC, P_C = 25 W at T_C = 25°C, h_FE = 100–250 (Class 16), and TO-126 package. It serves as a complement to BD380 in audio output and power control stages.

For engineers reviewing the BD37910STU datasheet, pinout, applications, or equivalent options, key selection criteria include collector-emitter sustaining voltage (V_CEO(sus) = 80 V), saturation performance (V_CE(sat) = 1 V @ I_C = 1 A, I_B = 0.1 A), thermal derating behavior, and safe operating area (SOA) limits under pulsed conditions.

Technical Context

This device operates as a single NPN bipolar junction transistor optimized for medium-power analog and switching roles in discrete amplifier output stages and relay/actuator drivers. Its design emphasizes high current gain linearity across I_C = 0.15–1 A, low V_CE(sat), and robust SOA up to 100 V / 2 A in continuous mode with proper heatsinking.

The BD37910STU exhibits specified turn-on (t_ON = 50 ns) and turn-off (t_OFF = 500 ns) times under defined test conditions (V_CC = 30 V, R_L = 60 Ω, I_B1 = −I_B2 = 0.05 A), supporting moderate-speed switching in industrial control and audio circuits where thermal stability and ruggedness are prioritized over RF performance.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 V - Maximum continuous collector-emitter voltage before breakdown; defines upper rail limit in linear amplifier or switch designs.
I_C (DC)	2 A - Continuous collector current rating; determines maximum sustained load drive capability with adequate heatsinking.
P_C @ T_C=25°C	25 W - Total power dissipation at case temperature 25°C; requires thermal management for operation above ambient.
h_FE Class	100–250 - DC current gain range (Class 16); ensures predictable base drive requirements across production lots.
V_CE(sat)	1 V @ I_C=1 A, I_B=0.1 A - Low saturation voltage minimizes conduction loss in switching applications.
t_OFF	500 ns - Measured turn-off delay under standardized pulse conditions; constrains maximum usable switching frequency.

Pinout & Package

BD37910STU is housed in a TO-126 plastic package with standard lead configuration: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. The package features a metal tab for mechanical mounting and thermal conduction to heatsinks.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path from transistor	Connected to ground or low-side reference; must handle full load current and support stable bias network return.
2 (Collector)	Current entry path into transistor	Connected to load or supply rail; electrically isolated from heatsink unless insulated mounting used.
3 (Base)	Control terminal for minority carrier injection	Requires current-limited drive (max I_B = 1 A); sensitive to ESD and transient overvoltage.

Key Features

Feature	Design Value
High V_CEO(sus)	80 V sustaining voltage enables reliable operation in 48 V industrial bus and audio amplifier rails without secondary clamping.
Classified h_FE	100–250 gain binning reduces need for individual circuit trimming and improves batch consistency in production.
Robust SOA	Defined safe operating area up to 100 V / 2 A supports short-duration overload tolerance in motor and solenoid drive.
Low V_BE(on)	1.5 V @ I_C = 1 A simplifies base drive design using standard logic-level or op-amp outputs.

Applications

Audio Power Amplifier Output Stage	Industrial Relay Driver
Use Scenario: Final push-pull stage in Class AB audio amplifiers delivering up to 20 W into 8 Ω loads. IC Role / Device Role / Timing Role: NPN output transistor conducting during positive half-cycle; paired with complementary PNP (e.g., BD380) for full-wave amplification. Use Value: High h_FE and low V_CE(sat) reduce crossover distortion and improve thermal efficiency at rated output power.	Use Scenario: Driving 24 V DC industrial relays with coil resistance ~200 Ω requiring 120 mA hold current. IC Role / Device Role / Timing Role: Single-ended switch controlling relay coil current; operated in saturation with base resistor biasing. Use Value: 2 A I_C rating and 25 W P_C allow margin for inrush current and extended duty cycles without thermal shutdown.
Motor Speed Controller (DC Brushed)	Power Supply Pass Transistor
Use Scenario: Low-frequency PWM-controlled H-bridge half-bridge leg driving 12–24 V brushed DC motors up to 1.5 A average current. IC Role / Device Role / Timing Role: High-side or low-side switching element; thermally coupled to aluminum chassis for passive cooling. Use Value: Verified t_OFF = 500 ns and SOA compliance ensure reliable commutation at ≤5 kHz PWM frequencies.	Use Scenario: Series pass element in linear regulated power supplies delivering 5–15 V at up to 1.8 A. IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output differential voltage. Use Value: 80 V V_CEO and 25 W P_C support ≥30 V input-to-output differentials while maintaining safe junction temperature.

Audio Power Amplifier Output Stage

Industrial Relay Driver

Use Scenario: Final push-pull stage in Class AB audio amplifiers delivering up to 20 W into 8 Ω loads.

IC Role / Device Role / Timing Role: NPN output transistor conducting during positive half-cycle; paired with complementary PNP (e.g., BD380) for full-wave amplification.

Use Value: High h_FE and low V_CE(sat) reduce crossover distortion and improve thermal efficiency at rated output power.

Use Scenario: Driving 24 V DC industrial relays with coil resistance ~200 Ω requiring 120 mA hold current.

IC Role / Device Role / Timing Role: Single-ended switch controlling relay coil current; operated in saturation with base resistor biasing.

Use Value: 2 A I_C rating and 25 W P_C allow margin for inrush current and extended duty cycles without thermal shutdown.

Motor Speed Controller (DC Brushed)

Power Supply Pass Transistor

Use Scenario: Low-frequency PWM-controlled H-bridge half-bridge leg driving 12–24 V brushed DC motors up to 1.5 A average current.

IC Role / Device Role / Timing Role: High-side or low-side switching element; thermally coupled to aluminum chassis for passive cooling.

Use Value: Verified t_OFF = 500 ns and SOA compliance ensure reliable commutation at ≤5 kHz PWM frequencies.

Use Scenario: Series pass element in linear regulated power supplies delivering 5–15 V at up to 1.8 A.

IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output differential voltage.

Use Value: 80 V V_CEO and 25 W P_C support ≥30 V input-to-output differentials while maintaining safe junction temperature.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BD379	Same die, identical electrical specs and TO-126 package; BD37910STU is a Fairchild-marked variant of BD379 with h_FE binned to Class 16 (100–250).	No functional difference; used interchangeably in legacy designs where BD379 is specified.	Select BD37910STU when Class 16 h_FE binning is required for consistent base drive design.
MJD31C	Higher V_CEO = 100 V, same I_C = 2 A, but TO-220 package; h_FE min = 20 (no classification), V_CE(sat) = 1.5 V @ I_C = 1.5 A.	TO-220 footprint requires PCB layout change; better SOA at high V_CE but higher saturation loss.	Choose MJD31C only if higher voltage headroom or TO-220 thermal interface is mandatory; not drop-in compatible.

Compared with BD379 (identical core device) and MJD31C (higher-voltage TO-220 alternative), BD37910STU offers guaranteed h_FE consistency and TO-126 mechanical compatibility-critical for space-constrained audio and industrial control boards where thermal path and footprint are fixed.

Availability

BD37910STU is available at Aetrix Electronics and suitable for audio power amplifiers, industrial relay drivers, DC motor controllers, and linear power supply designs requiring stable component supply with verified thermal and switching performance.

Supply support for BD37910STU 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The BD37910STU belongs to Fairchild's legacy medium-power linear and switching transistor family, engineered for robustness in audio output stages, industrial actuation, and analog power regulation where reliability under thermal stress is essential.

FAQ

What is the exact package type and pin configuration of BD37910STU?

BD37910STU uses the TO-126 plastic package with three leads: Pin 1 is Emitter, Pin 2 is Collector (connected to the metal tab), and Pin 3 is Base. This configuration is standardized across Fairchild's BD37x series and requires insulated mounting hardware when the tab is electrically connected to the collector.

Does BD37910STU have a specified junction-to-case thermal resistance (R_θJC)?

No R_θJC value is published in the BD37910STU datasheet. However, its 25 W power dissipation rating at T_C = 25°C implies typical R_θJC ≈ 1.0–1.2°C/W for TO-126 packages. For thermal design, use the provided power derating curve and ensure heatsink interface resistance remains below 0.5°C/W.

Is BD37910STU pin-compatible with BD375 or BD377?

Yes, BD37910STU shares identical TO-126 pinout and mechanical dimensions with BD375 and BD377. However, it is not functionally interchangeable due to higher voltage ratings: BD37910STU has V_CEO = 80 V vs. 45 V (BD375) and 60 V (BD377), so substitution requires verification of circuit voltage margins.

What is the maximum pulsed collector current (I_CP) rating for BD37910STU?

The BD37910STU is rated for I_CP = 3 A under pulsed conditions (PW = 350 µs, duty cycle = 2%). This allows brief current surges beyond the 2 A DC limit-useful for relay coil inrush or motor startup-provided average power stays within the SOA envelope and thermal mass prevents junction overheating.

Can BD37910STU be used in complementary pairs with PNP transistors?

Yes, BD37910STU is explicitly designed as the NPN complement to BD380 (PNP). Their matched V_CEO, I_C, and h_FE ranges enable balanced push-pull operation in Class AB audio amplifiers and H-bridge drivers without gain skew or thermal runaway risk.

BD37910STU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 2 A

Voltage - Collector Emitter Breakdown (Max):: 80 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 100mA, 1A

Current - Collector Cutoff (Max):: 2µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 63 @ 150mA, 2V

Power - Max:: 25 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

BD37910STU FAQ

1.How can I place an order for BD37910STU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD37910STU 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 BD37910STU reliable?

The price and inventory of BD37910STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD37910STU is usually 5 days.

3.What payment methods are accepted for BD37910STU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD37910STU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD37910STU?

BD37910STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD37910STU 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 BD37910STU?

For technical support, including BD37910STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD37910STU requirements.

6.How does Aetrix verify that BD37910STU is sourced from the original manufacturer or authorized distributors?

All BD37910STU 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 BD37910STU meets industry standards.

7.What is the process for return or replacement of BD37910STU?

All BD37910STU units undergo pre-shipment inspection (PSI). If there is an issue with BD37910STU, 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 BD37910STU part is unused and in its original packaging.

Return procedure for BD37910STU:

1.Submit a request within 90 days.

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

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