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

onsemi BD442STU

Name: BD442STU
Brand: onsemi
SKU: BD442STU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD442STU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BD442STU.pdf

Description:: TRANS PNP 80V 4A TO-126-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,728

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Product details

Overview

BD442STU from ON Semiconductor is a PNP epitaxial silicon power transistor in TO-126 package, rated for −80 V V_CEO, −4 A continuous collector current, and 36 W power dissipation at T_C = 25°C. It serves as a medium-power linear amplifier or switching device in DC motor drivers, relay drivers, and power supply output stages.

For engineers reviewing the BD442STU datasheet, pinout, applications, or equivalent options, key selection criteria include its −80 V blocking capability, h_FE range of 15–140 at I_C = −2 A, V_CE(sat) ≤ −0.8 V at I_C = −2 A / I_B = −0.2 A, and safe operating area validated up to 10 ms pulse width.

Technical Context

The BD442STU operates as a complementary PNP counterpart to the NPN BD441, enabling push-pull and H-bridge configurations. Its design emphasizes robust DC and pulsed current handling (I_CP = −7 A), with junction temperature tolerance up to 150°C and storage range from −65°C to +150°C.

Electrical behavior is characterized by low saturation voltage under high-current drive, stable DC current gain across I_C = −10 mA to −2 A, and minimal leakage (I_CBO ≤ −100 µA at V_CB = −80 V), supporting reliable operation in industrial control and power conversion circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−80 V - Maximum collector-emitter voltage before breakdown; enables use in 48 V and higher DC bus applications.
I_C (DC)	−4 A - Continuous collector current rating; supports sustained load switching without thermal derating at T_C ≤ 25°C.
P_C	36 W - Collector power dissipation at T_C = 25°C; defines heatsink sizing baseline for linear-mode operation.
h_FE	15–140 - DC current gain range at V_CE = −1 V; ensures predictable base drive requirements across production lots.
V_CE(sat)	≤ −0.8 V at I_C = −2 A / I_B = −0.2 A - Low saturation voltage minimizes conduction loss in switching applications.
f_T	3 MHz - Current gain bandwidth product at V_CE = −1 V, I_C = −250 mA; suitable for audio-frequency amplification and <100 kHz switching.

Pinout & Package

BD442STU is housed in a TO-126 plastic package with standard lead configuration: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. The case is electrically connected to the collector terminal.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for PNP operation	Connected to system ground or negative rail in common-emitter switch configurations.
2 (Collector)	Main current input terminal	Internally tied to metal tab; requires isolation from heatsink unless electrically referenced to same potential.
3 (Base)	Control electrode for bipolar conduction	Requires current-limited drive (max I_B = −1 A) to ensure safe turn-on/turn-off without secondary breakdown.

Key Features

Feature	Design Value
High V_CEO rating	−80 V enables direct interface with 48 V industrial buses and telecom power supplies without series stacking.
Robust SOA	Validated safe operating area up to 10 ms pulses supports inductive load switching with flyback energy absorption.
Low V_CE(sat)	≤ −0.8 V at I_C = −2 A reduces conduction losses by >30% vs. legacy PNP transistors with comparable ratings.
Thermal stability	Junction temperature limit of 150°C allows operation in enclosed enclosures with ambient up to 85°C when properly heatsinked.

Applications

DC Motor Control	Relay Driver
Use Scenario: Bidirectional 24–48 V brushed DC motor control in industrial actuators and HVAC dampers. IC Role / Device Role / Timing Role: PNP high-side switch in complementary emitter-follower output stage, paired with BD441. Use Value: −80 V V_CEO withstands back-EMF spikes during motor commutation; −0.8 V V_CE(sat) limits heat generation at 2 A stall current.	Use Scenario: Driving 12–48 V DC coil relays in PLC I/O modules and building automation panels. IC Role / Device Role / Timing Role: Medium-power saturated switch providing galvanic isolation between logic-level MCU outputs and relay coils. Use Value: 36 W power rating accommodates transient coil inrush currents; h_FE ≥ 15 ensures reliable turn-on with ≤10 mA base drive.
Linear Power Regulator	Switching Power Supply
Use Scenario: Pass transistor in adjustable linear regulators delivering up to 3 A at 5–24 V output. IC Role / Device Role / Timing Role: Series pass element dissipating excess voltage as heat; operated in active region with feedback control. Use Value: 150°C max junction temperature allows stable regulation under full-load conditions with moderate heatsinking.	Use Scenario: Output stage in offline flyback or forward converters with 36–72 V input rails. IC Role / Device Role / Timing Role: Synchronized PNP switch in quasi-resonant or fixed-frequency topologies requiring high-voltage blocking. Use Value: Validated SOA up to 100 µs pulse width supports reliable operation at 50–100 kHz switching frequencies.

DC Motor Control

Relay Driver

Use Scenario: Bidirectional 24–48 V brushed DC motor control in industrial actuators and HVAC dampers.

IC Role / Device Role / Timing Role: PNP high-side switch in complementary emitter-follower output stage, paired with BD441.

Use Value: −80 V V_CEO withstands back-EMF spikes during motor commutation; −0.8 V V_CE(sat) limits heat generation at 2 A stall current.

Use Scenario: Driving 12–48 V DC coil relays in PLC I/O modules and building automation panels.

IC Role / Device Role / Timing Role: Medium-power saturated switch providing galvanic isolation between logic-level MCU outputs and relay coils.

Use Value: 36 W power rating accommodates transient coil inrush currents; h_FE ≥ 15 ensures reliable turn-on with ≤10 mA base drive.

Linear Power Regulator

Switching Power Supply

Use Scenario: Pass transistor in adjustable linear regulators delivering up to 3 A at 5–24 V output.

IC Role / Device Role / Timing Role: Series pass element dissipating excess voltage as heat; operated in active region with feedback control.

Use Value: 150°C max junction temperature allows stable regulation under full-load conditions with moderate heatsinking.

Use Scenario: Output stage in offline flyback or forward converters with 36–72 V input rails.

IC Role / Device Role / Timing Role: Synchronized PNP switch in quasi-resonant or fixed-frequency topologies requiring high-voltage blocking.

Use Value: Validated SOA up to 100 µs pulse width supports reliable operation at 50–100 kHz switching frequencies.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11T4G	TO-252 (DPAK) package; −80 V V_CEO, −8 A I_C, but lower h_FE (10–60) and higher V_CE(sat) (−1.2 V @ −4 A).	Suitable for surface-mount designs where board space is constrained; less ideal for linear-mode operation due to higher saturation loss.	Select when automated assembly and compact layout are prioritized over thermal performance in through-hole systems.
BD442	Same die and specs as BD442STU; differs only in packaging notation-STU suffix denotes tape-and-reel packaging per ON Semiconductor's post-Fairchild nomenclature update.	No functional or electrical difference; identical pinout, SOA, and thermal characteristics.	BD442 is functionally identical and interchangeable; STU indicates tape-and-reel delivery format for volume production.

Compared with MJD44H11T4G and BD442, the BD442STU offers superior thermal management via TO-126 package, tighter h_FE consistency, and lower V_CE(sat), making it preferred for thermally demanding linear and medium-frequency switching roles where through-hole mounting is acceptable.

Availability

BD442STU is available at Aetrix Electronics and suitable for DC motor control, relay driving, and linear power regulation requiring stable component supply and long-term industrial availability.

Supply support for BD442STU 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 BD442STU belongs to ON Semiconductor's legacy power bipolar transistor family, originally developed by Fairchild and optimized for medium-power linear and switching applications in industrial controls and power supplies.

FAQ

What is the maximum continuous collector current rating for BD442STU?

The BD442STU has a maximum continuous collector current (I_C) rating of −4 A at case temperature T_C = 25°C. Derating is required above 25°C per the published power derating curve, reaching zero dissipation at T_C = 175°C. This rating applies under proper heatsinking and within the safe operating area limits defined in the BD442STU datasheet.

Is BD442STU pin-compatible with BD442?

Yes, BD442STU is pin-compatible with BD442 - both share identical TO-126 package dimensions, pinout (Emitter–Collector–Base), and electrical specifications. The "STU" suffix denotes tape-and-reel packaging per ON Semiconductor's updated nomenclature; no circuit or layout changes are needed when substituting BD442STU for BD442.

What is the typical V_CE(sat) of BD442STU under full-load conditions?

The BD442STU exhibits a typical V_CE(sat) of −0.8 V when operated at I_C = −2 A and I_B = −0.2 A. This value is measured at T_J = 25°C and reflects low conduction loss critical for efficiency in switching applications. Actual V_CE(sat) may increase slightly at elevated junction temperatures.

Can BD442STU be used in linear amplifier configurations?

Yes, BD442STU is explicitly designed for medium-power linear and switching applications. Its specified h_FE range (15–140), low distortion at audio frequencies, and validated SOA support Class-A and Class-AB amplifier stages, particularly in low-to-mid frequency (<100 kHz) power output sections where thermal management is maintained.

What is the junction temperature limit for BD442STU?

The BD442STU has a maximum rated junction temperature (T_J) of 150°C. Operation beyond this limit risks permanent degradation of the PNP epitaxial structure. Thermal design must ensure that steady-state and transient junction temperatures remain below 150°C, using the device's thermal resistance (R_θJC) and heatsink performance data from the BD442STU datasheet.

BD442STU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

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

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

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 200mA, 2A

Current - Collector Cutoff (Max):: 100µA

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

Power - Max:: 36 W

Frequency - Transition:: 3MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

BD442STU FAQ

1.How can I place an order for BD442STU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD442STU 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 BD442STU reliable?

The price and inventory of BD442STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD442STU is usually 5 days.

3.What payment methods are accepted for BD442STU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD442STU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD442STU?

BD442STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD442STU 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 BD442STU?

For technical support, including BD442STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD442STU requirements.

6.How does Aetrix verify that BD442STU is sourced from the original manufacturer or authorized distributors?

All BD442STU 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 BD442STU meets industry standards.

7.What is the process for return or replacement of BD442STU?

All BD442STU units undergo pre-shipment inspection (PSI). If there is an issue with BD442STU, 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 BD442STU part is unused and in its original packaging.

Return procedure for BD442STU:

1.Submit a request within 90 days.

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

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