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

onsemi BD440

Name: BD440
Brand: onsemi
SKU: BD440
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD440

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BD440.pdf

Description:: TRANS PNP 60V 4A TO-126

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BD440G from onsemi is a plastic medium-power silicon PNP bipolar junction transistor rated for 60 V collector-emitter voltage, 4.0 A continuous collector current, and 36 W total device dissipation at TC = 25°C. It operates across –55°C to +150°C junction temperature range and is RoHS-compliant with Pb-free packaging. It serves in linear amplification and hard-switching applications such as power supply regulators and motor drive stages.

For engineers reviewing the BD440G datasheet, pinout, applications, or equivalent options, key selection criteria include its V_CEO = 60 V rating, h_FE = 20 (min) at IC = 10 mA / V_CE = 5 V, V_CE(sat) ≤ 0.8 V at IC = 2.0 A / IB = 0.2 A, and TO-225 package thermal resistance R_θJC = 3.5°C/W.

Technical Context

The BD440G is a discrete PNP BJT optimized for medium-power switching and analog amplification. Its design supports DC current gain h_FE of 40 (min) at IC = 500 mA / V_CE = 1.0 V and 25 (min) at IC = 2.0 A / V_CE = 1.0 V, with f_T = 3.0 MHz under specified conditions.

It features complementary NPN counterparts BD437 and BD441, and belongs to a family sharing TO-225 (Case 77-09) mechanical outline, Pb-free marking convention, and identical pin configuration: Emitter–Collector–Base–Collector (pins 1–2–3–4). Thermal derating begins above 25°C at 288 mW/°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60 V - Maximum safe collector-emitter voltage before breakdown under open-base condition; defines upper rail limit in PNP switch designs.
I_C	4.0 A - Continuous DC collector current rating; sets maximum load-handling capability in linear or saturated operation.
P_D @ T_C = 25°C	36 W - Total power dissipation at case temperature 25°C; requires heatsinking for sustained high-current operation.
h_FE (IC = 10 mA)	20 (min) - Minimum DC current gain at low-signal bias; ensures predictable base drive sizing in amplifier stages.
V_CE(sat)	0.8 V max - Collector-emitter saturation voltage at IC = 2.0 A / IB = 0.2 A; determines conduction loss and heat generation in switching mode.
R_θJC	3.5 °C/W - Junction-to-case thermal resistance; enables calculation of junction temperature rise given measured case temperature and power dissipation.

Pinout & Package

BD440G is housed in a TO-225 package (Case 77-09, Style 1), featuring a metal tab connected to the collector and four leads in a single inline configuration. The package provides mechanical robustness and thermal path via the backside tab.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Main current exit terminal for PNP operation; connects to higher-potential rail in common-emitter configurations.
Pins 2 & 4	Collector	Shared collector terminals tied internally; both must be soldered or connected to heatsink/ground plane for optimal thermal and electrical performance.
Pin 3	Base	Control terminal for current amplification; requires current-limited drive to achieve target I_C without overdriving.

Key Features

Feature	Design Value
Pb-free and RoHS-compliant	Meets EU Directive 2011/65/EU; eliminates lead-based solder compatibility concerns and supports environmentally regulated production.
TO-225 mechanical outline	Standardized 4-pin single-inline package with collector-tab thermal interface; enables drop-in replacement in legacy board layouts using same footprint.
V_CEO = 60 V rating	Supports use in 48 V industrial bus systems and offline auxiliary supplies where moderate voltage headroom is required.
h_FE ≥ 25 @ IC = 2.0 A	Ensures sufficient gain at high current for reliable saturation in power switch applications without excessive base drive overhead.

Applications

DC Power Supply Regulation	Motor Drive Output Stage
Use Scenario: Used as series pass transistor in linear voltage regulators delivering up to 3 A at 12–24 V output. IC Role / Device Role / Timing Role: PNP pass element controlling output voltage via base bias; operates in active region for precision regulation. Use Value: Delivers low-noise, ripple-free output with V_CE(sat) ≤ 0.8 V minimizing dropout and thermal stress at full load.	Use Scenario: Employed as high-side switch in H-bridge or half-bridge motor control circuits driving brushed DC motors up to 100 W. IC Role / Device Role / Timing Role: PNP high-side switch enabling bidirectional current control when paired with NPN low-side complements. Use Value: Supports fast turn-on/turn-off with f_T = 3.0 MHz and maintains stable gain across 0.1–2.0 A load range for consistent torque response.
Audio Amplifier Driver	Industrial Relay Driver
Use Scenario: Drives output stage of Class AB audio amplifiers requiring 2–4 A peak current into 4 Ω loads. IC Role / Device Role / Timing Role: Medium-power PNP driver transistor handling signal swing and current delivery in push-pull output pairs. Use Value: Provides h_FE ≥ 40 at IC = 500 mA ensuring linear gain behavior and low distortion in mid-frequency bands.	Use Scenario: Interfaces microcontroller GPIO to energize 24 VDC industrial relays with coil currents up to 3.5 A. IC Role / Device Role / Timing Role: Saturated switch providing galvanic isolation and current amplification between logic-level control and inductive load. Use Value: With V_BE(ON) = 1.5 V and V_CE(sat) ≤ 0.8 V, ensures minimal power loss and reliable relay pull-in even with marginal supply margins.

DC Power Supply Regulation

Motor Drive Output Stage

Use Scenario: Used as series pass transistor in linear voltage regulators delivering up to 3 A at 12–24 V output.

IC Role / Device Role / Timing Role: PNP pass element controlling output voltage via base bias; operates in active region for precision regulation.

Use Value: Delivers low-noise, ripple-free output with V_CE(sat) ≤ 0.8 V minimizing dropout and thermal stress at full load.

Use Scenario: Employed as high-side switch in H-bridge or half-bridge motor control circuits driving brushed DC motors up to 100 W.

IC Role / Device Role / Timing Role: PNP high-side switch enabling bidirectional current control when paired with NPN low-side complements.

Use Value: Supports fast turn-on/turn-off with f_T = 3.0 MHz and maintains stable gain across 0.1–2.0 A load range for consistent torque response.

Audio Amplifier Driver

Industrial Relay Driver

Use Scenario: Drives output stage of Class AB audio amplifiers requiring 2–4 A peak current into 4 Ω loads.

IC Role / Device Role / Timing Role: Medium-power PNP driver transistor handling signal swing and current delivery in push-pull output pairs.

Use Value: Provides h_FE ≥ 40 at IC = 500 mA ensuring linear gain behavior and low distortion in mid-frequency bands.

Use Scenario: Interfaces microcontroller GPIO to energize 24 VDC industrial relays with coil currents up to 3.5 A.

IC Role / Device Role / Timing Role: Saturated switch providing galvanic isolation and current amplification between logic-level control and inductive load.

Use Value: With V_BE(ON) = 1.5 V and V_CE(sat) ≤ 0.8 V, ensures minimal power loss and reliable relay pull-in even with marginal supply margins.

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
BD442G	V_CEO = 80 V (vs. 60 V), same TO-225 package and pinout; h_FE min = 15 @ IC = 10 mA.	Higher voltage margin suitable for 60–75 V bus systems; lower small-signal gain may require adjusted base drive network.	Select BD442G when operating above 60 V or needing extended SOA at elevated V_CE; verify base resistor values for reduced h_FE.
MJD44H11G	TO-252 (DPAK) package; V_CEO = 80 V, I_C = 8 A, R_θJC = 2.0°C/W; higher power capability but different footprint.	Surface-mount alternative with superior thermal performance; not mechanically interchangeable with BD440G's through-hole TO-225.	Choose MJD44H11G for new SMT designs requiring higher current or better thermal management; redesign PCB layout required.

Compared with BD440G, BD442G offers higher voltage tolerance with identical mounting and pinout, while MJD44H11G delivers greater current and thermal efficiency in a surface-mount package-neither is pin-compatible without layout changes, but both serve overlapping medium-power PNP switching roles.

Availability

BD440G is available at Aetrix Electronics and suitable for DC power supply regulation, motor drive output stages, and industrial relay driver circuits requiring stable component supply and long-term manufacturability support.

Supply support for BD440G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BD440G belongs to onsemi's legacy medium-power discrete transistor family designed for cost-sensitive, high-reliability industrial control and power conversion applications where proven thermal and electrical performance is prioritized over advanced integration.

FAQ

What is the maximum collector-emitter voltage rating for BD440G?

The BD440G has a maximum collector-emitter voltage (V_CEO) rating of 60 V DC under open-base conditions. This value is confirmed in the Absolute Maximum Ratings table of the official onsemi datasheet (Rev. 17, August 2024) and defines the upper voltage limit for safe operation in common-emitter configurations. Exceeding this rating risks avalanche breakdown and permanent device damage.

Is BD440G compatible with BD442G in the same PCB footprint?

Yes, BD440G and BD442G share identical TO-225 (Case 77-09, Style 1) packaging, pin assignment (Emitter–Collector–Base–Collector), and mechanical dimensions. They are physically interchangeable on the same PCB layout, though BD442G offers higher V_CEO = 80 V and slightly lower h_FE, requiring verification of base drive and voltage margin in the target application.

What is the thermal resistance from junction to case for BD440G?

The BD440G has a thermal resistance from junction to case (R_θJC) of 3.5°C/W, as specified in the Thermal Characteristics section of the onsemi datasheet. This parameter enables accurate junction temperature estimation when the case temperature and power dissipation are known, supporting proper heatsink selection for continuous 4.0 A operation.

Does BD440G have a complementary NPN transistor?

Yes, the BD440G has a designated complementary NPN counterpart: the BD441. Both devices share matching voltage ratings, current capabilities, and TO-225 packaging, enabling balanced push-pull or H-bridge implementations. This pairing is explicitly stated in the Features section of the BD438/D datasheet and validated across electrical characteristics tables.

What is the minimum DC current gain (h_FE) of BD440G at 2.0 A collector current?

The BD440G guarantees a minimum DC current gain (h_FE) of 25 at IC = 2.0 A, V_CE = 1.0 V, and TC = 25°C, per the Electrical Characteristics table in the onsemi BD438/D datasheet. This value ensures adequate gain for saturated switching applications without requiring excessive base current, directly impacting drive circuit efficiency and thermal design.

BD440 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 300mA, 3A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 500mA, 1V

Power - Max:: 36 W

Frequency - Transition:: 3MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126

BD440 FAQ

1.How can I place an order for BD440 through Aetrix?

Please submit a Request for Quotation (RFQ) for BD440 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 BD440 reliable?

The price and inventory of BD440 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD440 is usually 5 days.

3.What payment methods are accepted for BD440?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD440 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD440?

BD440 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD440 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 BD440?

For technical support, including BD440 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD440 requirements.

6.How does Aetrix verify that BD440 is sourced from the original manufacturer or authorized distributors?

All BD440 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 BD440 meets industry standards.

7.What is the process for return or replacement of BD440?

All BD440 units undergo pre-shipment inspection (PSI). If there is an issue with BD440, 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 BD440 part is unused and in its original packaging.

Return procedure for BD440:

1.Submit a request within 90 days.

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

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