Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

STMicroelectronics BD140

Name: BD140
Brand: STMicroelectronics
SKU: BD140
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BD140

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

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

Datasheet:: BD140.pdf

Description:: TRANS PNP 80V 1.5A SOT-32-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:5,029

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BD140 from STMicroelectronics is a complementary PNP bipolar junction transistor (BJT) designed for audio amplifier and driver stages in quasi-complementary output circuits. It features V_CEO = −80 V, I_C = −1.5 A, h_FE = 25–250 (at I_C = −150 mA), R_thj-case = 10 °C/W, and SOT-32 package - enabling robust low-voltage power amplification in consumer audio equipment.

For engineers reviewing the BD140 datasheet, BD140 pinout, BD140 application, or BD140 equivalent, key selection criteria include its negative collector-emitter sustaining voltage (V_CEO(sus) = −80 V), DC current gain grouping (e.g., BD140-10 vs. BD140-16), saturation voltage (V_CE(sat) = −0.5 V at I_C = −0.5 A), thermal resistance, and compatibility with BD139 NPN counterparts in push-pull configurations.

Technical Context

The BD140 operates as a medium-power PNP BJT with epitaxial planar construction and is optimized for linear amplification rather than switching. Its design supports complementary symmetry with BD139 (NPN), sharing identical SOT-32 mechanical footprint and thermal performance (R_thj-case = 10 °C/W).

It delivers stable h_FE across three test conditions (I_C = −5/−150/−500 mA), exhibits low leakage (I_CBO ≤ −10 µA at T_C = 125 °C), and maintains V_BE ≈ −1 V under rated drive - confirming suitability for Class AB audio output stages requiring matched gain and thermal tracking.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−80 V: Maximum safe collector-emitter voltage with base open; defines headroom for high-swing audio rails.
I_C	−1.5 A: Continuous DC collector current; sets peak output capability in linear amplifier designs.
h_FE	25–250: DC current gain range at I_C = −150 mA; enables bias stability tuning across production lots.
V_CE(sat)	−0.5 V @ I_C = −0.5 A, I_B = −0.05 A: Low saturation voltage minimizes power loss in emitter-follower or driver stages.
R_thj-case	10 °C/W: Junction-to-case thermal resistance; allows direct heatsink mounting for 12.5 W dissipation at T_C ≤ 25 °C.
P_TOT (T_amb)	1.25 W @ T_amb ≤ 25 °C: Ambient-rated power limit; determines derating slope (12.5 mW/°C above 25 °C).

Pinout & Package

The BD140 is housed in the SOT-32 (TO-126) plastic package - a through-hole, single-ended power transistor outline with integrated heat slug. Pin 1 is Emitter, Pin 2 is Base, Pin 3 is Collector (viewed from front, flat side facing user, leads down).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit terminal for PNP device	Connected to common rail or load return; electrically tied to heatsink tab in PCB layout.
2 (Base)	Control input for minority-carrier injection	Receives bias current to regulate collector current; requires series resistor for gain-stable operation.
3 (Collector)	Main current input terminal	Connected to negative supply rail in typical audio output stage; thermally coupled to heatsink via metal tab.

Key Features

Feature	Design Value
Complementary pairing	Matched thermal and electrical specs with BD139 NPN for symmetrical push-pull amplifier stages.
Pre-selected h_FE groups	BD140-10 (h_FE = 63–160) and BD140-16 (h_FE = 100–250) enable consistent gain binning in production.
ECOPACK® compliance	Lead-free second-level interconnect per JEDEC JESD97; supports RoHS-compliant manufacturing.
High V_CEO(sus)	−80 V sustaining voltage ensures reliability under transient overvoltage in reactive speaker loads.

Applications

Hi-Fi Audio Amplifier Output Stage

DC Motor Driver (Low-Voltage)

Use Scenario: Final output stage in 20–50 W stereo amplifier using quasi-complementary topology with BD139/BD140 pair.

IC Role / Device Role / Timing Role: PNP power transistor delivering negative half-cycle current to 4–8 Ω loudspeaker load.

Use Value: High h_FE consistency and low V_CE(sat) reduce crossover distortion and thermal drift versus generic transistors.

Use Scenario: H-bridge low-side switch controlling bidirectional 12 V DC motor in office automation devices.

IC Role / Device Role / Timing Role: PNP switch in emitter-follower configuration driving motor return path with fast turn-off via base pull-up.

Use Value: −80 V V_CEO withstands inductive kickback without snubber; 1.5 A rating supports 10 W continuous motor drive.

LED Constant-Current Driver

Linear Voltage Regulator Pass Element

Use Scenario: Adjustable constant-current source for high-brightness LED arrays in signage applications.

IC Role / Device Role / Timing Role: Series pass transistor regulating current through LED string via feedback-controlled base bias.

Use Value: Stable h_FE across temperature ensures ±5% current regulation; SOT-32 tab enables direct heatsinking for 1+ W dissipation.

Use Scenario: Pass element in adjustable linear regulator supplying ±15 V analog circuitry from unregulated ±24 V rails.

IC Role / Device Role / Timing Role: PNP series regulator transistor sinking current from negative rail to ground reference.

Use Value: −1.5 A I_C and 12.5 W P_TOT support >500 mA load current with <10 °C/W thermal path to heatsink.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJE15034	V_CEO = −250 V, I_C = −8 A, h_FE = 20–60 - higher voltage/current but lower gain and wider spread.	Suitable for high-voltage industrial amplifiers; over-specified for consumer audio where BD140's gain matching matters.	Choose when >−80 V breakdown or >−1.5 A current is required; avoid if h_FE consistency or thermal footprint matching is critical.
BC558	V_CEO = −30 V, I_C = −100 mA, h_FE = 110–800 - lower power, higher gain variability, TO-92 package.	Limited to preamp or signal-level switching; cannot replace BD140 in output stage due to power/thermal limits.	Use only in low-power bias networks or logic interfaces; not a functional substitute in power amplification roles.

Compared with MJE15034 and BC558, the BD140 uniquely balances moderate voltage rating (−80 V), controlled h_FE spread, and SOT-32 thermal interface - making it optimal for cost-sensitive, thermally constrained audio output stages where gain symmetry with BD139 is essential.

Availability

BD140 is available at Aetrix Electronics and suitable for Hi-Fi audio amplifiers, DC motor drivers, LED constant-current sources, and linear voltage regulator designs requiring stable component supply and long-term manufacturability.

Supply support for BD140 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.

The BD140 belongs to ST's legacy bipolar power transistor product line, engineered specifically for audio frequency linear amplification and complementary driver applications with emphasis on thermal reliability and gain consistency.

FAQ

Is BD140 pin-compatible with BD139?

No - BD140 (PNP) and BD139 (NPN) share identical SOT-32 package dimensions and pinout order (Emitter-Base-Collector), but their polarity and biasing requirements are opposite. They are complementary, not interchangeable. Layout must respect PNP/NPN current flow direction and supply polarity.

What is the maximum safe operating temperature for BD140?

The BD140 has a maximum junction temperature (T_j) of 150 °C and storage temperature range of −65 to +150 °C. To sustain 12.5 W dissipation, case temperature must remain ≤25 °C; above that, power must be linearly derated at 125 mW/°C per the datasheet's derating curve.

Does BD140 require a heatsink in typical audio applications?

Yes - when dissipating >1 W continuously (e.g., >200 mA at V_CE ≈ 5 V), thermal resistance to ambient (100 °C/W) causes rapid junction temperature rise. Mounting the SOT-32 tab to a minimum 10 cm² aluminum heatsink reduces R_thj-amb sufficiently for reliable 1.25 W ambient operation.

How does BD140-10 differ from BD140-16?

Both share identical absolute ratings and package. BD140-10 is binned for h_FE = 63–160 at I_C = −150 mA; BD140-16 for h_FE = 100–250. The -16 variant offers higher minimum gain, beneficial for low-base-drive designs; the -10 provides tighter mid-range gain control in matched pairs with BD139-10.

BD140 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

Product Status:: Active

Transistor Type:: PNP

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-32-3

BD140 FAQ

1.How can I place an order for BD140 through Aetrix?

Please submit a Request for Quotation (RFQ) for BD140 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 BD140 reliable?

The price and inventory of BD140 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD140 is usually 5 days.

3.What payment methods are accepted for BD140?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD140 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD140?

BD140 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD140 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 BD140?

For technical support, including BD140 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD140 requirements.

6.How does Aetrix verify that BD140 is sourced from the original manufacturer or authorized distributors?

All BD140 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 BD140 meets industry standards.

7.What is the process for return or replacement of BD140?

All BD140 units undergo pre-shipment inspection (PSI). If there is an issue with BD140, 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 BD140 part is unused and in its original packaging.

Return procedure for BD140:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…