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

onsemi BD239BTU

Name: BD239BTU
Brand: onsemi
SKU: BD239BTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD239BTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD239BTU.pdf

Description:: TRANS NPN 80V 2A TO-220-3

Quantity:: RFQ Add To RFQ list

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Inventory:5,233

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Product details

Overview

BD239BTU from ON Semiconductor is an NPN epitaxial silicon power transistor in TO-220 package, rated for 80 V V_CEO, 2 A continuous collector current, and 30 W collector dissipation at T_C = 25°C. It serves as a medium-power linear amplifier or switching device in DC motor drivers, power supplies, and relay drivers.

For engineers reviewing the BD239BTU datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO = 80 V, h_FE ≥ 40 at I_C = 0.2 A, V_CE(sat) ≤ 0.7 V at I_C = 1 A / I_B = 0.2 A, thermal performance in TO-220, and complementary pairing with BD240B.

Technical Context

The BD239BTU operates as a single NPN bipolar junction transistor optimized for medium-power linear and switching applications. Its V_CEO = 80 V and V_CER = 90 V support robust blocking in inductive load circuits, while its 150°C maximum junction temperature enables operation in thermally constrained industrial environments.

Designed for DC gain stability and low saturation voltage, it delivers h_FE ≥ 15 at I_C = 1 A and V_CE(sat) = 0.7 V under specified drive conditions - enabling efficient base-driven switching without external bias networks in many implementations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 V - Maximum collector-emitter voltage before breakdown under open-base condition; defines safe operating voltage ceiling in switching applications.
I_C (DC)	2 A - Continuous collector current rating; sets maximum steady-state load current capability with adequate heatsinking.
P_C	30 W - Collector power dissipation at T_C = 25°C; determines thermal design margin and heatsink sizing requirements.
h_FE	40 (min) at I_C = 0.2 A - DC current gain ensures reliable base drive scaling for low-to-moderate current amplification stages.
V_CE(sat)	0.7 V max at I_C = 1 A, I_B = 0.2 A - Low saturation voltage minimizes conduction loss and self-heating during on-state operation.
T_J	150°C - Maximum junction temperature; allows operation in industrial ambient up to ~85°C with appropriate thermal resistance.

Pinout & Package

BD239BTU uses the standard TO-220 package with 3 leads: Base (pin 1), Collector (pin 2), Emitter (pin 3). The metal tab is electrically connected to the collector and must be isolated from chassis ground unless circuit topology requires collector-to-heatsink connection.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives forward-biased current to turn on the transistor; requires current-limiting resistor in most driver circuits.
2 (Collector)	High-side output node	Connected to load and supply rail; metal tab is collector-connected - isolation required if heatsink is grounded.
3 (Emitter)	Current return path	Serves as common reference for base drive and load return; often tied to system ground or low-side switch node.

Key Features

Feature	Design Value
Complementary pairing	Matched as NPN counterpart to BD240B PNP transistor - enables push-pull and H-bridge designs without gain mismatch.
High V_CER	90 V - Enhanced collector-emitter sustaining voltage improves ruggedness against inductive kickback in relay/motor control.
Low V_BE(on)	1.3 V at I_C = 1 A - Reduces base drive power requirement and eases compatibility with 3.3 V/5 V logic-level controllers.
TO-220 mechanical standard	Industry-standard footprint and mounting hole - supports drop-in replacement and widely available heatsink compatibility.

Applications

DC Motor Driver Stage	Linear Voltage Regulator Pass Element
Use Scenario: Driving 24 V, 1.5 A brushed DC motors in industrial actuators with PWM-controlled speed regulation. IC Role / Device Role / Timing Role: NPN power switch controlling motor current path between supply and ground. Use Value: V_CEO = 80 V provides 3× overvoltage margin against back-EMF spikes; 30 W dissipation supports intermittent 2 A loads without forced cooling.	Use Scenario: High-current series pass element in adjustable 3–24 V, 1.8 A linear regulators for analog sensor subsystems. IC Role / Device Role / Timing Role: Linear-mode current amplifier regulating output voltage via base bias control. Use Value: h_FE ≥ 40 ensures stable closed-loop gain; 150°C T_J rating accommodates ambient temperatures up to 70°C with passive heatsinking.
Relay Driver Interface	Power Supply Foldback Limiter
Use Scenario: Driving 12 V/500 mA electromagnetic relays in PLC I/O modules with optocoupler-isolated control inputs. IC Role / Device Role / Timing Role: Switching transistor providing galvanically isolated coil energization path. Use Value: V_CE(sat) ≤ 0.7 V limits relay coil voltage drop to <10%, ensuring reliable pull-in across temperature range.	Use Scenario: Current-limiting element in foldback protection circuitry of 15 V, 2 A bench power supplies. IC Role / Device Role / Timing Role: Active current-sensing switch that reduces output voltage under overload to limit power dissipation. Use Value: I_C = 2 A rating and 30 W P_C allow sustained operation during fault conditions without thermal runaway.

DC Motor Driver Stage

Linear Voltage Regulator Pass Element

Use Scenario: Driving 24 V, 1.5 A brushed DC motors in industrial actuators with PWM-controlled speed regulation.

IC Role / Device Role / Timing Role: NPN power switch controlling motor current path between supply and ground.

Use Value: V_CEO = 80 V provides 3× overvoltage margin against back-EMF spikes; 30 W dissipation supports intermittent 2 A loads without forced cooling.

Use Scenario: High-current series pass element in adjustable 3–24 V, 1.8 A linear regulators for analog sensor subsystems.

IC Role / Device Role / Timing Role: Linear-mode current amplifier regulating output voltage via base bias control.

Use Value: h_FE ≥ 40 ensures stable closed-loop gain; 150°C T_J rating accommodates ambient temperatures up to 70°C with passive heatsinking.

Relay Driver Interface

Power Supply Foldback Limiter

Use Scenario: Driving 12 V/500 mA electromagnetic relays in PLC I/O modules with optocoupler-isolated control inputs.

IC Role / Device Role / Timing Role: Switching transistor providing galvanically isolated coil energization path.

Use Value: V_CE(sat) ≤ 0.7 V limits relay coil voltage drop to <10%, ensuring reliable pull-in across temperature range.

Use Scenario: Current-limiting element in foldback protection circuitry of 15 V, 2 A bench power supplies.

IC Role / Device Role / Timing Role: Active current-sensing switch that reduces output voltage under overload to limit power dissipation.

Use Value: I_C = 2 A rating and 30 W P_C allow sustained operation during fault conditions without thermal runaway.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BD239C	V_CEO = 100 V (vs. 80 V); otherwise identical pinout, package, and gain specs.	Higher voltage margin for 48 V systems or enhanced surge immunity.	Select BD239C when operating above 60 V DC bus or requiring higher avalanche energy tolerance.
MJE239	Same V_CEO = 80 V, but TO-220AB package variant with different lead frame geometry; h_FE min = 30 at I_C = 0.2 A.	Lower minimum h_FE may require increased base drive in marginal gain applications.	Use MJE239 only where legacy board layout tolerates minor mechanical variance and gain margin is verified.

Compared with BD239BTU, BD239C offers higher voltage headroom without changing layout or drive, while MJE239 trades slight h_FE reduction for alternate manufacturing lineage - both require validation of thermal interface and base drive network under actual load conditions.

Availability

BD239BTU is available at Aetrix Electronics and suitable for DC motor drivers, linear regulator pass elements, relay interfaces, and power supply protection circuits requiring stable component supply and long-term industrial availability.

Supply support for BD239BTU 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and cloud power applications.

BD239BTU belongs to ON Semiconductor's legacy Fairchild discrete transistor portfolio, engineered for medium-power linear amplification and robust switching in industrial control and power conversion systems.

FAQ

What is the maximum collector-emitter voltage rating for BD239BTU?

The BD239BTU has a maximum collector-emitter voltage (V_CEO) rating of 80 V at T_C = 25°C. This value is confirmed in the Absolute Maximum Ratings table and applies under open-base conditions. Exceeding this voltage risks avalanche breakdown and permanent device failure. Derating is required at elevated case temperatures per the datasheet thermal curves.

Is BD239BTU pin-compatible with BD239B or BD239C?

Yes, BD239BTU is pin-compatible with BD239B and BD239C - all share identical TO-220 package, pin 1 (Base), pin 2 (Collector), pin 3 (Emitter) assignment, and mechanical dimensions. The suffix "TU" denotes tape-and-reel packaging; electrical differences are limited to V_CEO/V_CER ratings across the A/B/C variants.

What is the typical DC current gain (hFE) of BD239BTU at 1 A collector current?

The BD239BTU specifies a minimum h_FE of 15 at V_CE = 4 V and I_C = 1 A. While typical values may reach 25–40 depending on unit variation and temperature, design must use the guaranteed minimum of 15 to ensure sufficient base drive under worst-case conditions.

Does BD239BTU have a built-in base-emitter resistor?

No, BD239BTU is a standard three-terminal NPN bipolar transistor with no integrated base-emitter resistor. It requires external base current limiting - typically via a series resistor driven by a microcontroller GPIO or logic buffer - to prevent excessive base current and ensure reliable saturation.

Can BD239BTU be used in parallel for higher current handling?

BD239BTU is not recommended for direct paralleling without individual emitter resistors due to positive temperature coefficient of V_BE and gain mismatch. Uneven current sharing can cause thermal runaway. For >2 A applications, use a single higher-rated device (e.g., MJE13009) or implement active current balancing.

BD239BTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

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:: 700mV @ 200mA, 1A

Current - Collector Cutoff (Max):: 300µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 15 @ 1A, 4V

Power - Max:: 30 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BD239BTU FAQ

1.How can I place an order for BD239BTU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD239BTU 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 BD239BTU reliable?

The price and inventory of BD239BTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD239BTU is usually 5 days.

3.What payment methods are accepted for BD239BTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD239BTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD239BTU?

BD239BTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD239BTU 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 BD239BTU?

For technical support, including BD239BTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD239BTU requirements.

6.How does Aetrix verify that BD239BTU is sourced from the original manufacturer or authorized distributors?

All BD239BTU 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 BD239BTU meets industry standards.

7.What is the process for return or replacement of BD239BTU?

All BD239BTU units undergo pre-shipment inspection (PSI). If there is an issue with BD239BTU, 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 BD239BTU part is unused and in its original packaging.

Return procedure for BD239BTU:

1.Submit a request within 90 days.

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

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