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

STMicroelectronics BD239C

Name: BD239C
Brand: STMicroelectronics
SKU: BD239C
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD239C

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD239C.pdf

Description:: TRANS NPN 100V 2A TO-220

Quantity:: RFQ Add To RFQ list

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Inventory:2,366

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Product details

Overview

BD239C from STMicroelectronics is an NPN silicon power transistor in TO-220 package, designed for general-purpose switching and linear amplification. It delivers 2 A continuous collector current, 30 W case-power dissipation at 25°C, and low V_CE(sat) of 0.7 V at I_C = 1 A / I_B = 0.2 A, enabling efficient high-current drive in motor control and power supply circuits.

For engineers reviewing the BD239C datasheet, BD239C pinout, BD239C application, or BD239C equivalent, key selection criteria include its 100 V V_CEO, 40–150 h_FE range at I_C = 0.2–1 A, 150°C max junction temperature, and TO-220 mechanical compatibility with standard heatsinks.

Technical Context

The BD239C uses Planar technology with "Base Island" layout to achieve high DC current gain and low saturation voltage simultaneously. Its safe operating area (SOA) supports pulsed operation up to 4 A peak collector current with 1.5% duty cycle, and derating begins at T_case > 25°C per the published thermal curve.

It operates as a single-element NPN bipolar junction transistor with no integrated biasing, protection, or driver circuitry. Base-emitter turn-on voltage is 1.3 V at I_C = 1 A and V_CE = 4 V, and emitter-base breakdown is rated at 5 V, limiting base drive design margins.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	100 V - Maximum collector-emitter voltage with base open; defines maximum blocking capability in switch applications.
I_C	2 A - Continuous DC collector current; sets steady-state load drive capacity without forced cooling.
P_TOT (T_case ≤ 25°C)	30 W - Total power dissipation limit at case temperature ≤25°C; requires heatsink for sustained operation.
V_CE(sat)	0.7 V @ I_C=1 A, I_B=0.2 A - Low saturation voltage reduces conduction loss and heat generation in switching mode.
h_FE	40–150 @ I_C=0.2–1 A - Wide DC current gain range affects base drive current design and stability in linear amplifiers.
T_J(max)	150°C - Maximum junction temperature; determines thermal design margin and reliability under overload conditions.
V_EBO	5 V - Emitter-base reverse breakdown voltage; constrains negative base drive or AC-coupled base bias networks.

Pinout & Package

BD239C is housed in a TO-220 package with three leads: emitter (pin 1), base (pin 2), collector (pin 3). The collector is internally connected to the metal tab, requiring electrical isolation when mounted to heatsinks.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for base-emitter bias; connects to ground or low-side return path in common-emitter configurations.
2 (Base)	Control input	Receives forward-biased current to saturate or linearly bias the transistor; requires current-limiting resistor in most drive circuits.
3 (Collector)	High-side current source	Connected to load and supply rail; electrically tied to metal tab-must be insulated from chassis or heatsink unless referenced to system ground.

Key Features

Feature	Design Value
Planar "Base Island" structure	Enables simultaneous high h_FE and low V_CE(sat) without trade-off, improving efficiency in Class-A/B amplifiers and PWM drivers.
TO-220 mechanical form factor	Standardized footprint and mounting hole spacing compatible with off-the-shelf heatsinks and PCB layouts for power discrete devices.
ECOPACK® lead-free packaging	Meets RoHS Directive 2011/65/EU and JEDEC JESD97; second-level interconnect is lead-free with marked category on package and inner box label.
150°C maximum junction temperature	Supports operation in high-ambient environments (e.g., enclosed industrial enclosures) with appropriate thermal management.

Applications

DC Motor Control

Linear Audio Amplifier

Use Scenario: Driving brushed DC motors up to 24 V / 1.5 A in industrial actuators and robotics.

IC Role / Device Role / Timing Role: NPN power switch in common-emitter configuration, controlled by microcontroller GPIO via base resistor network.

Use Value: Low 0.7 V V_CE(sat) minimizes I²R losses during on-state, reducing thermal stress and extending motor driver lifetime.

Use Scenario: Output stage in low-fidelity audio amplifiers for public address systems and intercoms.

IC Role / Device Role / Timing Role: Single-ended Class-A or Class-AB output transistor delivering up to 1.5 W into 8 Ω loads.

Use Value: High h_FE (≥40 at 0.2 A) enables stable biasing with minimal base drive current, simplifying passive bias networks.

Switch-Mode Power Supply

Relay Driver Circuit

Use Scenario: Main switching transistor in low-frequency (<10 kHz), low-power flyback or forward converters.

IC Role / Device Role / Timing Role: Primary-side switch controlling energy transfer from input to transformer primary winding.

Use Value: 100 V V_CEO rating supports 24–48 V input rails with margin for voltage spikes and ringing.

Use Scenario: Solid-state replacement for electromechanical relays in PLC I/O modules and HVAC controllers.

IC Role / Device Role / Timing Role: High-current interface between logic-level controller and 12–24 V relay coil.

Use Value: 4 A I_CM peak current handles relay inrush without secondary snubbing, improving reliability over mechanical contacts.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BD239D	Higher h_FE (min 80 @ I_C=0.2 A), same V_CEO/I_C/package	Better suited for low-base-drive applications where gain consistency is critical	Select BD239D when base drive current is constrained or gain variation must be minimized across temperature.
TIP31C	Lower V_CEO (100 V vs. BD239C's 100 V - identical), but higher I_C (3 A), larger SOA, different pinout (E-B-C)	Requires PCB layout change; better for higher-current switching where thermal headroom is available	Choose TIP31C only if board redesign is acceptable and 3 A continuous current is required with same voltage rating.

Compared with BD239D and TIP31C, the BD239C offers balanced gain, saturation voltage, and thermal performance in the standard TO-220 footprint-making it optimal for cost-sensitive, medium-power designs where pinout compatibility and predictable h_FE behavior are prioritized over extreme current or gain specs.

Availability

BD239C is available at Aetrix Electronics and suitable for DC motor control, linear audio amplification, relay driving, and low-frequency switch-mode power supplies requiring stable component supply and long-term industrial availability.

Supply support for BD239C 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power discrete technologies with vertical manufacturing capabilities.

The BD239C belongs to ST's legacy bipolar power transistor family, engineered for robustness and manufacturability in high-volume industrial power interfaces-not optimized for RF or ultra-high-speed switching.

FAQ

Is BD239C RoHS-compliant and lead-free?

Yes, BD239C is supplied in ECOPACK® packaging with lead-free second-level interconnect, compliant with RoHS Directive 2011/65/EU. The lead-free status is marked on both the device package and inner box label per JEDEC JESD97 standards.

What is the recommended heatsink requirement for continuous 2 A operation?

At 2 A and V_CE(sat) ≈ 0.7 V, power dissipation is ~1.4 W. With R_θJC ≈ 1.7°C/W (from TO-220 thermal data), a heatsink with R_θSA ≤ 10°C/W is recommended to maintain T_J < 125°C at 25°C ambient, assuming proper mounting torque and thermal interface material.

Can BD239C replace BD239B in existing designs?

Yes-BD239C is a direct upgrade of BD239B with identical pinout, package, and voltage/current ratings, but improved h_FE (min 40 vs. min 25) and tighter V_CE(sat) specification. No layout or schematic changes are needed for drop-in replacement.

Does BD239C have built-in protection features like thermal shutdown or overcurrent limiting?

No, BD239C is a bare silicon bipolar transistor with no integrated protection circuitry. External components-including base current limiting, collector snubbers, and heatsink-mounted thermal cutoff switches-are required for safe operation under fault conditions.

BD239C Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Active

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 100 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:: 2 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

BD239C FAQ

1.How can I place an order for BD239C through Aetrix?

Please submit a Request for Quotation (RFQ) for BD239C 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 BD239C reliable?

The price and inventory of BD239C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD239C is usually 5 days.

3.What payment methods are accepted for BD239C?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD239C transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD239C?

BD239C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD239C 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 BD239C?

For technical support, including BD239C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD239C requirements.

6.How does Aetrix verify that BD239C is sourced from the original manufacturer or authorized distributors?

All BD239C 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 BD239C meets industry standards.

7.What is the process for return or replacement of BD239C?

All BD239C units undergo pre-shipment inspection (PSI). If there is an issue with BD239C, 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 BD239C part is unused and in its original packaging.

Return procedure for BD239C:

1.Submit a request within 90 days.

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

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