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

STMicroelectronics BD139-10

Name: BD139-10
Brand: STMicroelectronics
SKU: BD139-10
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD139-10

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

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

Datasheet:: BD139-10.pdf

Description:: TRANS NPN 80V 1.5A SOT-32

Quantity:: RFQ Add To RFQ list

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Inventory:5,790

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Product details

Overview

BD139-10 from STMicroelectronics is an NPN epitaxial planar bipolar junction transistor in SOT-32 package, pre-selected for h_FE = 63–100 at I_C = 150 mA, V_CE = 2 V, with V_CEO = 80 V, I_C = 1.5 A, and P_TOT = 12.5 W (T_C ≤ 25 °C). It serves as a medium-power audio driver in complementary quasi-complementary amplifier stages.

For engineers reviewing the BD139-10 datasheet, BD139-10 pinout, BD139-10 application, or BD139-10 equivalent, key selection criteria include DC current gain grouping, safe operating area under pulsed conditions, thermal resistance (R_thj-case = 10 °C/W), collector-emitter sustaining voltage (V_CEO(sus) = 80 V), and base-emitter voltage (V_BE = 1 V @ I_C = 0.5 A).

Technical Context

This NPN BJT operates in linear amplification and switching modes, optimized for audio frequency ranges up to several hundred kHz. Its design emphasizes stable h_FE grouping (BD139-10 = 63–100), low V_CE(sat) (0.5 V @ I_C = 0.5 A, I_B = 0.05 A), and robust SOA compliance per Figure 2 of the datasheet.

The device uses epitaxial planar construction with ECOPACK® lead-free interconnects and is rated for T_j = 150 °C maximum. Thermal derating follows R_thj-amb = 100 °C/W and R_thj-case = 10 °C/W, enabling heatsink-assisted operation in Class AB amplifier output stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 V - Maximum continuous collector-emitter voltage before breakdown under open-base condition
I_C	1.5 A - Continuous DC collector current rating at T_C ≤ 25 °C
h_FE group	63–100 - Pre-selected DC current gain range at I_C = 150 mA, V_CE = 2 V for consistent biasing in matched pairs
V_CE(sat)	0.5 V - Low saturation voltage ensures minimal power loss in switching or saturated driver applications
P_TOT	12.5 W - Total power dissipation limit at case temperature ≤ 25 °C, requiring heatsinking above ambient
R_thj-case	10 °C/W - Junction-to-case thermal resistance enables efficient heat transfer to external heatsink

Pinout & Package

BD139-10 is housed in the SOT-32 (TO-126) plastic package: a 3-pin, single-ended, through-hole molded case with emitter-tab configuration. The tab is electrically connected to the collector terminal.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for majority carriers	Low-impedance terminal tied to ground or negative rail in common-emitter amplifier configurations
2 (Base)	Control electrode for minority carrier injection	Receives bias current to regulate collector current; requires current-limiting resistor in discrete driver circuits
3 (Collector / Tab)	Main current collection node and thermal interface	Electrically and thermally connected to metal tab; must be isolated from chassis unless circuit design permits common-collector grounding

Key Features

Feature	Design Value
Pre-selected h_FE group	63–100 at I_C = 150 mA ensures predictable DC bias stability in push-pull output stages
High V_CEO(sus)	80 V sustaining voltage supports operation in 40–60 V rail audio amplifiers without secondary clamping
Low V_CE(sat)	0.5 V at I_C = 0.5 A minimizes conduction loss and self-heating in Class AB drivers
ECOPACK® compliance	Lead-free second-level interconnect meets JEDEC JESD97 and RoHS requirements for industrial assembly

Applications

Audio Power Amplifier Output Stage

DC Motor Driver (Small Brushed)

Use Scenario: Final push-pull stage in 10–20 W stereo amplifier using quasi-complementary topology with BD139-10 (NPN) and BD140-10 (PNP).

IC Role / Device Role / Timing Role: Medium-power NPN switch/amplifier delivering linear current gain and low distortion at audio frequencies.

Use Value: Pre-selected h_FE matching reduces quiescent current drift and improves thermal symmetry with complementary PNP pair.

Use Scenario: H-bridge half-bridge leg driving 12 V, 1 A brushed DC motor in industrial actuator control.

IC Role / Device Role / Timing Role: Discrete NPN switch controlling motor current direction and on/off timing via PWM base drive.

Use Value: 80 V V_CEO accommodates inductive kickback without snubber; 12.5 W P_TOT supports 100% duty-cycle operation with heatsink.

Linear Voltage Regulator Pass Element

Relay Driver Interface

Use Scenario: Series pass transistor in adjustable 0–30 V, 1.5 A linear bench power supply with foldback current limiting.

IC Role / Device Role / Timing Role: High-current, high-V_CEO series regulator element dissipating up to 12.5 W under worst-case dropout.

Use Value: R_thj-case = 10 °C/W enables direct mounting to aluminum chassis for passive thermal management.

Use Scenario: Base-driven switch activating 24 V, 100 mA electromagnetic relay in PLC I/O module.

IC Role / Device Role / Timing Role: General-purpose NPN interface transistor providing galvanic isolation between logic-level MCU and inductive load.

Use Value: V_BE = 1 V @ I_C = 0.5 A ensures reliable turn-on with standard 3.3 V/5 V GPIO; IC_BO ≤ 0.1 µA prevents leakage-induced false triggering.

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
BD139-16	h_FE group = 100–160 (higher gain, wider spread)	Suitable where higher small-signal gain is needed but less critical bias stability	Select BD139-16 when designing for higher loop gain or lower base drive current; avoid in tightly matched complementary pairs.
MJE13003	V_CEO = 400 V, I_C = 1.5 A, h_FE = 10–40 - higher voltage, lower and ungrouped gain	Used in SMPS primary switches and high-voltage linear regulators, not audio amplifiers	Choose MJE13003 only for high-voltage switching; not interchangeable due to gain mismatch and SOA differences.

Compared with BD139-10, BD139-16 offers higher but less tightly controlled h_FE, while MJE13003 trades audio-grade linearity and gain consistency for high-voltage ruggedness-making BD139-10 uniquely suited for gain-critical, thermally balanced audio driver roles.

Availability

BD139-10 is available at Aetrix Electronics and suitable for audio amplifier output stages, DC motor drivers, linear voltage regulator pass elements, and relay interface circuits requiring stable component supply across prototyping, pilot production, and long-lifecycle industrial programs.

Supply support for BD139-10 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

BD139-10 belongs to ST's legacy general-purpose bipolar transistor product line, engineered specifically for cost-sensitive, medium-power linear and switching applications in audio, power supply, and industrial control systems.

FAQ

Is BD139-10 pin-compatible with BD139 or BD139-16?

Yes - all BD139 variants (including BD139, BD139-10, and BD139-16) share identical SOT-32 (TO-126) mechanical footprint and pinout: Emitter (pin 1), Base (pin 2), Collector/Tab (pin 3). Only electrical parameters - especially h_FE grouping - differ between suffixes.

What is the maximum safe continuous collector current at 70 °C case temperature?

At T_C = 70 °C, derating from 12.5 W (at 25 °C) applies: P_D = 12.5 W − (70−25) °C × (12.5 W / 125 °C) = 8.75 W. With V_CE(sat) ≈ 0.5 V, max continuous I_C ≈ √(P_D/r_CE) ≈ 1.2 A assuming typical r_CE; actual limit depends on heatsink efficiency and ambient airflow.

Can BD139-10 be used in place of BD135-16 in an existing design?

Only with circuit validation: BD139-10 has V_CEO = 80 V vs. BD135-16's 45 V, and h_FE group 63–100 vs. 160–250. Higher voltage improves margin, but lower gain may reduce loop stability or require base resistor adjustment in amplifier bias networks.

Does BD139-10 require a heatsink in a 10 W Class AB amplifier output stage?

Yes - at 10 W dissipation, junction temperature rise ΔT_j = P × R_thj-amb = 10 W × 100 °C/W = 1000 °C (exceeding 150 °C). Even with R_thj-case = 10 °C/W, a heatsink reducing R_thcase-amb to ≤ 5 °C/W is required to hold T_j < 150 °C at full output.

BD139-10 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 1.5 A

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

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 50mA, 500mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 150mA, 2V

Power - Max:: 1.25 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: SOT-32

BD139-10 FAQ

1.How can I place an order for BD139-10 through Aetrix?

Please submit a Request for Quotation (RFQ) for BD139-10 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 BD139-10 reliable?

The price and inventory of BD139-10 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD139-10 is usually 5 days.

3.What payment methods are accepted for BD139-10?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD139-10 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD139-10?

BD139-10 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD139-10 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 BD139-10?

For technical support, including BD139-10 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD139-10 requirements.

6.How does Aetrix verify that BD139-10 is sourced from the original manufacturer or authorized distributors?

All BD139-10 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 BD139-10 meets industry standards.

7.What is the process for return or replacement of BD139-10?

All BD139-10 units undergo pre-shipment inspection (PSI). If there is an issue with BD139-10, 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 BD139-10 part is unused and in its original packaging.

Return procedure for BD139-10:

1.Submit a request within 90 days.

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

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