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

onsemi BD239ATU

Name: BD239ATU
Brand: onsemi
SKU: BD239ATU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD239ATU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD239ATU.pdf

Description:: TRANS NPN 60V 2A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BD239ATU from ON Semiconductor is an NPN epitaxial silicon power transistor in TO-220 package, rated for 60 V V_CEO, 2 A continuous collector current, and 30 W power 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 BD239ATU datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO rating, h_FE consistency at 1 A, V_CE(sat) under 0.7 V, thermal performance in TO-220, and complementary pairing with BD240A.

Technical Context

The BD239ATU operates as a single NPN bipolar junction transistor optimized for medium-power linear and switching applications. Its design supports DC biasing with h_FE ≥ 40 at I_C = 0.2 A and ≥ 15 at I_C = 1 A, and features V_CE(sat) ≤ 0.7 V at I_C = 1 A / I_B = 0.2 A.

It is specified for operation up to 150°C junction temperature and includes absolute maximum ratings for V_CER = 70 V, V_EBO = 5 V, and I_CP = 4 A (pulsed), enabling robust use in industrial control circuits where transient overvoltage and short-duration surge currents occur.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60 V - Maximum DC collector-emitter voltage before breakdown; defines safe operating range in switching applications.
I_C (DC)	2 A - Continuous collector current capability; sets upper limit for steady-state load drive.
P_C	30 W - Thermal power limit at case temperature 25°C; requires heatsinking above ~1.5 W ambient dissipation.
h_FE	40–15 - DC current gain of 40 at 0.2 A, dropping to 15 at 1 A; informs base drive sizing for saturation.
V_CE(sat)	≤ 0.7 V - Low saturation voltage at I_C = 1 A / I_B = 0.2 A; minimizes conduction loss in switch mode.
T_J	150°C - Maximum allowable junction temperature; constrains thermal design margin under sustained load.

Pinout & Package

BD239ATU 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 unless intentionally tied to collector potential.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Receives forward-biased current to turn on transistor; requires ~0.2 A for full saturation at 1 A collector load.
2 (Collector)	Power output node	Connected to load and supply rail; metal tab is collector-connected and thermally critical for heat transfer.
3 (Emitter)	Current return path	Common reference for base drive and load return; grounded in low-side switch configurations.

Key Features

Feature	Design Value
Complementary pairing	Designed as NPN counterpart to BD240A PNP; enables push-pull and H-bridge topologies without redesign.
High V_CER	70 V rating allows safe operation during inductive kickback in relay/motor switching without snubber.
Stable h_FE across current range	Specified min/max h_FE at both 0.2 A and 1 A ensures predictable base drive requirements across load conditions.
TO-220 mechanical standardization	Industry-standard footprint and mounting hole spacing enable drop-in replacement and heatsink compatibility.

Applications

DC Motor Driver Stage	Linear Regulator Pass Element
Use Scenario: Driving 12 V, 1.5 A brushed DC motors in industrial actuators with PWM-controlled speed. IC Role / Device Role / Timing Role: NPN power switch controlling motor current path to ground (low-side configuration). Use Value: V_CE(sat) ≤ 0.7 V limits power loss to < 1.05 W at full load, reducing heatsink size vs. higher-V_sat alternatives.	Use Scenario: Acting as series pass transistor in adjustable 0–24 V, 1.5 A linear power supply. IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output differential. Use Value: 30 W P_C and 150°C T_J support continuous operation at 12 V dropout × 1.5 A = 18 W dissipation with proper heatsinking.
Relay Driver Interface	Audio Power Amplifier Output Stage
Use Scenario: Switching 24 V/1 A electromagnetic relays in PLC I/O modules with optocoupler-isolated base drive. IC Role / Device Role / Timing Role: High-current interface between logic-level controller and inductive relay coil. Use Value: V_CER = 70 V withstands > 100 V flyback spikes without clamping diode, simplifying BOM.	Use Scenario: Output stage in 5 W Class AB audio amplifier for public address systems. IC Role / Device Role / Timing Role: Linear amplification of audio signal with minimal crossover distortion. Use Value: h_FE ≥ 15 at 1 A ensures stable biasing and gain linearity across dynamic audio loads.

DC Motor Driver Stage

Linear Regulator Pass Element

Use Scenario: Driving 12 V, 1.5 A brushed DC motors in industrial actuators with PWM-controlled speed.

IC Role / Device Role / Timing Role: NPN power switch controlling motor current path to ground (low-side configuration).

Use Value: V_CE(sat) ≤ 0.7 V limits power loss to < 1.05 W at full load, reducing heatsink size vs. higher-V_sat alternatives.

Use Scenario: Acting as series pass transistor in adjustable 0–24 V, 1.5 A linear power supply.

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

Use Value: 30 W P_C and 150°C T_J support continuous operation at 12 V dropout × 1.5 A = 18 W dissipation with proper heatsinking.

Relay Driver Interface

Audio Power Amplifier Output Stage

Use Scenario: Switching 24 V/1 A electromagnetic relays in PLC I/O modules with optocoupler-isolated base drive.

IC Role / Device Role / Timing Role: High-current interface between logic-level controller and inductive relay coil.

Use Value: V_CER = 70 V withstands > 100 V flyback spikes without clamping diode, simplifying BOM.

Use Scenario: Output stage in 5 W Class AB audio amplifier for public address systems.

IC Role / Device Role / Timing Role: Linear amplification of audio signal with minimal crossover distortion.

Use Value: h_FE ≥ 15 at 1 A ensures stable biasing and gain linearity across dynamic audio loads.

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	Higher V_CEO = 100 V; same package, h_FE, and P_C.	Preferred in 48 V systems or high-surge environments where 60 V margin is insufficient.	Select BD239C only if system transients exceed 60 V; otherwise BD239ATU offers optimal cost/performance balance.
MJE239	Same V_CEO = 60 V, but TO-220AB package with insulated tab; h_FE min 30 at 1 A.	Used where collector isolation from heatsink is required (e.g., floating ground designs).	Choose MJE239 when electrical isolation of collector from mounting surface is mandatory; BD239ATU requires insulating hardware.

Compared with BD239C and MJE239, the BD239ATU provides the best combination of voltage margin, gain stability, and thermal efficiency for 24–36 V industrial switching applications where collector-to-heatsink isolation is not required.

Availability

BD239ATU is available at Aetrix Electronics and suitable for DC motor drivers, linear regulator pass elements, and relay driver interfaces requiring stable component supply and long-term industrial availability.

Supply support for BD239ATU 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 energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BD239ATU belongs to ON Semiconductor's legacy power bipolar transistor product line, engineered for reliability in medium-power linear and switching applications where ruggedness, thermal stability, and complementary pairing are essential.

FAQ

What is the maximum continuous collector current rating for BD239ATU?

The BD239ATU is rated for 2 A continuous collector current (I_C) at case temperature T_C = 25°C. Derating is required above this temperature per the thermal resistance curve in the official ON Semiconductor datasheet. At 100°C case temperature, the usable I_C drops to approximately 1.3 A. Always verify thermal design using the BD239ATU's R_θJC = 2.5°C/W and actual heatsink performance.

Is BD239ATU pin-compatible with BD239 or BD239B?

Yes, BD239ATU is pin-compatible with all BD239 family variants (BD239, BD239A, BD239B, BD239C) because they share identical TO-220 package dimensions and terminal assignments (Base–Collector–Emitter). However, voltage ratings differ: BD239ATU has V_CEO = 60 V, while BD239 is 45 V and BD239B is 80 V. Substitution requires verification of voltage stress margins in the target circuit.

Does BD239ATU require a heatsink in typical applications?

Yes, BD239ATU requires a heatsink whenever power dissipation exceeds ~1.5 W continuously. With P_C = 30 W at T_C = 25°C and R_θJC = 2.5°C/W, even moderate loads (e.g., 1 A at 1.5 V V_CE) generate 1.5 W - enough to raise junction temperature beyond safe limits without thermal management. The BD239ATU datasheet specifies minimum heatsink requirements based on ambient temperature and airflow.

What is the guaranteed h_FE range for BD239ATU at 1 A collector current?

The BD239ATU guarantees h_FE ≥ 15 at V_CE = 4 V and I_C = 1 A, per the ON Semiconductor datasheet. This minimum ensures reliable saturation with 0.2 A base drive. Typical h_FE is higher (~25–40), but design must use the guaranteed minimum. The BD239ATU's h_FE is tested and binned during production to meet this specification.

Can BD239ATU be used as a direct replacement for Fairchild's original BD239A?

Yes, BD239ATU is the ON Semiconductor–branded successor to Fairchild's BD239A following the acquisition. It maintains identical electrical specifications, package, pinout, and thermal characteristics. ON Semiconductor confirms functional equivalence and recommends BD239ATU for new designs and legacy replacements where BD239A was previously used. No PCB or schematic changes are needed.

BD239ATU 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):: 60 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

BD239ATU FAQ

1.How can I place an order for BD239ATU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD239ATU 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 BD239ATU reliable?

The price and inventory of BD239ATU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD239ATU is usually 5 days.

3.What payment methods are accepted for BD239ATU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD239ATU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD239ATU?

BD239ATU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD239ATU 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 BD239ATU?

For technical support, including BD239ATU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD239ATU requirements.

6.How does Aetrix verify that BD239ATU is sourced from the original manufacturer or authorized distributors?

All BD239ATU 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 BD239ATU meets industry standards.

7.What is the process for return or replacement of BD239ATU?

All BD239ATU units undergo pre-shipment inspection (PSI). If there is an issue with BD239ATU, 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 BD239ATU part is unused and in its original packaging.

Return procedure for BD239ATU:

1.Submit a request within 90 days.

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

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