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

onsemi BD242ATU

Name: BD242ATU
Brand: onsemi
SKU: BD242ATU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD242ATU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD242ATU.pdf

Description:: TRANS PNP 60V 3A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BD242ATU from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon power transistor in TO-220 package, rated for -60 V V_CEO, -3 A continuous collector current, and 40 W power dissipation at T_C = 25°C, used in medium-power linear regulation and switching circuits such as DC motor drivers and relay interfaces.

For engineers reviewing the BD242ATU datasheet, pinout, applications, or equivalent options, key selection factors include its -60 V V_CEO, -3 A I_C, h_FE ≥ 25 at -1 A, V_CE(sat) ≤ -1.2 V, and TO-220 thermal performance in industrial control and power supply designs.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined sustaining voltage (V_CEO(sus) = -60 V), low saturation voltage (-1.2 V at -3 A/-0.6 A), and base-emitter turn-on voltage of -1.8 V. Its h_FE drops from min 25 at -1 A to min 10 at -3 A, indicating gain compression under high-current drive.

Designed for medium-power linear and switching applications, BD242ATU complements BD241ATU and shares identical TO-220 mechanical outline and thermal interface. It supports DC bias networks requiring stable current gain over temperature and pulse operation up to 5 A with ≤2% duty cycle.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-60 V - Maximum safe collector-emitter voltage before breakdown in open-base configuration
I_C (DC)	-3 A - Continuous collector current rating defining steady-state power stage capacity
P_C	40 W - Maximum power dissipation at case temperature 25°C, requiring heatsink for sustained operation
h_FE	25 (min) at -1 A - DC current gain sufficient for low-base-drive switching in relay/motor control
V_CE(sat)	-1.2 V (max) at -3 A/-0.6 A - Low saturation voltage enabling <1.8 W conduction loss at full load
T_J	150°C - Maximum junction temperature limiting thermal design margin in enclosed environments

Pinout & Package

BD242ATU uses the standard TO-220 package with isolated tab (collector-connected), 3-pin vertical lead frame, and 2.54 mm pin pitch. Mounting hole Ø3.60 mm enables mechanical fixation and thermal coupling to heatsinks.

Pin/Terminal	Circuit Role	Design Meaning
1 (Left)	Base	Current-controlled input terminal; requires ~0.6 A base drive for full saturation at -3 A collector current
2 (Center)	Collector	Main current path terminal; electrically connected to metal tab for direct heatsink mounting and thermal conduction
3 (Right)	Emitter	Common return node in PNP configuration; tied to positive rail in high-side switch topologies

Key Features

Feature	Design Value
Complementary Pairing	Matched to BD241ATU for push-pull amplifier stages and H-bridge driver symmetry
High V_CEO(sus)	-60 V sustaining voltage ensures reliable operation under inductive load flyback transients
Low V_CE(sat)	-1.2 V max reduces conduction losses and self-heating in 24 V DC motor control
TO-220 Thermal Interface	Isolated collector tab allows direct mounting to heatsink without insulating washer in grounded-chassis systems

Applications

DC Motor Control	Relay Driver
Use Scenario: Bidirectional 24 V brushed DC motor control in industrial actuators using complementary PNP/NPN pairs. IC Role / Device Role / Timing Role: High-side PNP switch providing current sink path during reverse polarity phase. Use Value: -60 V V_CEO withstands back-EMF spikes; -1.2 V V_CE(sat) limits power loss to <1.8 W at 3 A.	Use Scenario: Solid-state replacement for electromechanical relays in PLC output modules. IC Role / Device Role / Timing Role: Medium-power PNP switch driving 24 V/1 A relay coils with TTL-compatible base input. Use Value: h_FE ≥ 25 at -1 A enables direct microcontroller GPIO drive without external amplification.
Linear Regulator Pass Element	Power Supply Sequencing
Use Scenario: Adjustable negative linear regulator delivering -5 V to -15 V at up to 2 A in lab bench supplies. IC Role / Device Role / Timing Role: Series pass transistor regulating output by varying base current in response to error amplifier feedback. Use Value: 40 W power rating and 150°C T_J support thermally robust operation with active heatsinking.	Use Scenario: Controlled power-up sequencing of dual-rail analog/digital subsystems in test equipment. IC Role / Device Role / Timing Role: Delayed-enable PNP switch isolating secondary supply rail until primary rail stabilizes. Use Value: -3 A I_C and -60 V V_CEO ensure margin against cross-rail fault conditions during transient events.

DC Motor Control

Relay Driver

Use Scenario: Bidirectional 24 V brushed DC motor control in industrial actuators using complementary PNP/NPN pairs.

IC Role / Device Role / Timing Role: High-side PNP switch providing current sink path during reverse polarity phase.

Use Value: -60 V V_CEO withstands back-EMF spikes; -1.2 V V_CE(sat) limits power loss to <1.8 W at 3 A.

Use Scenario: Solid-state replacement for electromechanical relays in PLC output modules.

IC Role / Device Role / Timing Role: Medium-power PNP switch driving 24 V/1 A relay coils with TTL-compatible base input.

Use Value: h_FE ≥ 25 at -1 A enables direct microcontroller GPIO drive without external amplification.

Linear Regulator Pass Element

Power Supply Sequencing

Use Scenario: Adjustable negative linear regulator delivering -5 V to -15 V at up to 2 A in lab bench supplies.

IC Role / Device Role / Timing Role: Series pass transistor regulating output by varying base current in response to error amplifier feedback.

Use Value: 40 W power rating and 150°C T_J support thermally robust operation with active heatsinking.

Use Scenario: Controlled power-up sequencing of dual-rail analog/digital subsystems in test equipment.

IC Role / Device Role / Timing Role: Delayed-enable PNP switch isolating secondary supply rail until primary rail stabilizes.

Use Value: -3 A I_C and -60 V V_CEO ensure margin against cross-rail fault conditions during transient events.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD242G	TO-263 surface-mount package; same -60 V V_CEO, -3 A I_C, but lower P_C (35 W) and no isolated tab	Suitable for automated SMT assembly; requires PCB copper area instead of external heatsink	Select when board space is constrained and thermal management is via PCB layout rather than mechanical heatsink
BD242C	Same TO-220 package and pinout; higher -100 V V_CEO and -90 V V_CER, but identical h_FE and V_CE(sat) specs	Used where higher voltage margin is required, e.g., 48 V battery systems with load dump transients	Select when system-level overvoltage protection exceeds -60 V, with no change to drive circuit or layout

Compared with MJD242G and BD242C, BD242ATU provides optimal balance of through-hole manufacturability, 40 W thermal capability via isolated tab, and -60 V rating for 24–36 V industrial power rails-making it preferred for serviceable, heatsink-mounted legacy designs.

Availability

BD242ATU is available at Aetrix Electronics and suitable for DC motor control, relay driving, linear regulator pass elements, and power supply sequencing requiring stable component supply across long-lifecycle industrial programs.

Supply support for BD242ATU 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 supplier focused on energy-efficient electronics, with heritage from Fairchild Semiconductor's analog and discrete product lines.

BD242ATU belongs to the BD24x family of medium-power PNP transistors designed for industrial linear regulation, switching, and complementary pair use in motor drives and power supplies.

FAQ

What is the maximum collector-emitter voltage rating for BD242ATU?

The BD242ATU has a maximum collector-emitter voltage (V_CEO) rating of -60 V at T_C = 25°C. This value is confirmed in the Absolute Maximum Ratings table and repeated in the Electrical Characteristics section as V_CEO(sus) under pulsed test conditions. Exceeding this voltage risks avalanche breakdown and permanent device failure.

Does BD242ATU have an electrically isolated collector tab?

Yes, BD242ATU features an electrically isolated collector tab in its TO-220 package. The center pin (pin 2) and metal tab are internally connected to the collector, but the tab is insulated from the mounting surface-enabling direct heatsink attachment without short-circuit risk in grounded-chassis systems.

What is the minimum DC current gain (h_FE) of BD242ATU at -3 A collector current?

The minimum DC current gain (h_FE) of BD242ATU at V_CE = -4 V and I_C = -3 A is 10, as specified in the Electrical Characteristics table. This reduced gain compared to the 25 minimum at -1 A reflects expected gain compression under high-current operation.

Can BD242ATU be used as a direct replacement for BD242B in a circuit?

No, BD242ATU is not a direct replacement for BD242B. BD242B has -80 V V_CEO and -90 V V_CER, while BD242ATU is rated for -60 V V_CEO. Substituting BD242ATU in a BD242B-design may result in premature breakdown if circuit transients exceed -60 V.

What is the base-emitter on voltage (V_BE(on)) specification for BD242ATU?

The base-emitter on voltage (V_BE(on)) for BD242ATU is -1.8 V maximum, measured at V_CE = -4 V and I_C = -3 A. This parameter defines the forward-biased base-emitter junction drop required to achieve full conduction, critical for calculating base resistor values in switch-mode applications.

BD242ATU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 3 A

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

Vce Saturation (Max) @ Ib, Ic:: 1.2V @ 600mA, 3A

Current - Collector Cutoff (Max):: 300µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 25 @ 1A, 4V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BD242ATU FAQ

1.How can I place an order for BD242ATU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD242ATU 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 BD242ATU reliable?

The price and inventory of BD242ATU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD242ATU is usually 5 days.

3.What payment methods are accepted for BD242ATU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD242ATU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD242ATU?

BD242ATU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD242ATU 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 BD242ATU?

For technical support, including BD242ATU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD242ATU requirements.

6.How does Aetrix verify that BD242ATU is sourced from the original manufacturer or authorized distributors?

All BD242ATU 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 BD242ATU meets industry standards.

7.What is the process for return or replacement of BD242ATU?

All BD242ATU units undergo pre-shipment inspection (PSI). If there is an issue with BD242ATU, 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 BD242ATU part is unused and in its original packaging.

Return procedure for BD242ATU:

1.Submit a request within 90 days.

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

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