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

onsemi BDX54ATU

Name: BDX54ATU
Brand: onsemi
SKU: BDX54ATU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BDX54ATU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BDX54ATU.pdf

Description:: TRANS PNP DARL 60V 8A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BDX54ATU from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon Darlington transistor in TO-220 package, rated for -60 V V_CEO, -8 A DC collector current, 60 W power dissipation at T_C = 25°C, with h_FE ≥ 750 at I_C = -3 A, and integrated damper diode. It serves as a high-current switching element in audio amplifier output stages and hammer driver circuits.

For engineers reviewing the BDX54ATU datasheet, pinout, applications, or equivalent options, key selection criteria include its -60 V blocking capability, -12 A pulsed current rating, V_CE(sat) ≤ -2 V at I_C = -3 A / I_B = -12 mA, integrated parallel diode forward voltage of -1.8 V at I_F = -3 A, and TO-220 thermal performance under sustained load.

Technical Context

The BDX54ATU operates as a monolithic PNP Darlington pair with built-in emitter-base clamp and an integrated damper diode across C–E, enabling safe inductive load switching without external flyback protection. Its high h_FE minimizes base drive requirements while maintaining robust SOA up to 100 V and 10 A in pulse mode.

Designed for linear and switching operation, it supports V_CEO(sus) = -60 V at I_C = -100 mA with zero base current, exhibits I_CBO ≤ -200 µA at V_CB = -60 V, and delivers V_BE(sat) ≤ -2.5 V under full-rated conduction - critical for low-loss power stage design.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-60 V - maximum continuous collector-emitter blocking voltage, defines safe operating range in switching applications
I_C (DC)	-8 A - steady-state current handling capacity, sets thermal design baseline for heatsink sizing
P_C	60 W @ T_C = 25°C - total power dissipation limit before thermal derating begins
h_FE	≥750 @ V_CE = -3 V, I_C = -3 A - high DC gain reduces required base drive current and driver complexity
V_CE(sat)	≤ -2 V @ I_C = -3 A, I_B = -12 mA - low saturation voltage minimizes conduction loss and heat generation
VF (diode)	-1.8 V @ I_F = -3 A - integrated damper diode clamps inductive kickback, eliminating need for external flyback diode

Pinout & Package

BDX54ATU uses the standard TO-220 package with vertical mounting orientation, metal tab electrically connected to collector, and thermally optimized leadframe for PCB heatsinking via screw-mount or clip attachment.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives base current to enable conduction; requires current-limiting resistor in series with driver
2 (Collector)	Main power output terminal	Connected to metal tab; must be isolated from chassis unless circuit ground reference permits
3 (Emitter)	Power return path	Serves as common emitter node; polarity reversal relative to NPN devices affects bias network layout

Key Features

Feature	Design Value
Integrated damper diode	Eliminates external flyback diode requirement in relay/hammer/solenoid drivers, reducing BOM count and board space
High h_FE (≥750)	Reduces base drive current demand by >3× vs. standard PNP transistors, easing microcontroller or logic-level interface design
TO-220 mechanical footprint	Enables direct replacement in legacy designs using industry-standard heatsinks and mounting hardware
V_CEO(sus) = -60 V	Supports reliable operation in 48 V industrial bus systems and automotive battery-supplied loads with margin

Applications

Audio Amplifier Output Stage	Electromechanical Hammer Driver
Use Scenario: Final push-pull output stage in Class AB audio amplifiers delivering up to 50 W into 8 Ω loads. IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current, low-distortion negative half-cycle amplification. Use Value: High h_FE ensures stable biasing with minimal quiescent current drift; integrated diode prevents crossover distortion during fast signal transitions.	Use Scenario: Driving electromagnetic hammers in dot-matrix printers and industrial marking equipment. IC Role / Device Role / Timing Role: High-current, fast-turn-off switch controlling solenoid coil energization and collapse timing. Use Value: V_CEO(sus) = -60 V withstands back-EMF spikes; integrated damper diode ensures consistent hammer impact force and extends coil life.
DC Motor Direction Control	Industrial Relay Interface
Use Scenario: Low-side switching in H-bridge motor control for 24–48 V brushed DC motors in factory automation. IC Role / Device Role / Timing Role: Complementary PNP switch in dual-H configuration enabling bidirectional rotation and dynamic braking. Use Value: -8 A DC rating supports peak stall currents; TO-220 thermal mass sustains intermittent overload without thermal shutdown.	Use Scenario: Isolated control of 120/240 VAC relays via optocoupler-driven base interface in PLC I/O modules. IC Role / Device Role / Timing Role: High-voltage, high-current interface transistor translating logic signals to relay coil drive. Use Value: -60 V V_CEO provides margin against line transients; low V_CE(sat) reduces self-heating during extended coil hold periods.

Audio Amplifier Output Stage

Electromechanical Hammer Driver

Use Scenario: Final push-pull output stage in Class AB audio amplifiers delivering up to 50 W into 8 Ω loads.

IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current, low-distortion negative half-cycle amplification.

Use Value: High h_FE ensures stable biasing with minimal quiescent current drift; integrated diode prevents crossover distortion during fast signal transitions.

Use Scenario: Driving electromagnetic hammers in dot-matrix printers and industrial marking equipment.

IC Role / Device Role / Timing Role: High-current, fast-turn-off switch controlling solenoid coil energization and collapse timing.

Use Value: V_CEO(sus) = -60 V withstands back-EMF spikes; integrated damper diode ensures consistent hammer impact force and extends coil life.

DC Motor Direction Control

Industrial Relay Interface

Use Scenario: Low-side switching in H-bridge motor control for 24–48 V brushed DC motors in factory automation.

IC Role / Device Role / Timing Role: Complementary PNP switch in dual-H configuration enabling bidirectional rotation and dynamic braking.

Use Value: -8 A DC rating supports peak stall currents; TO-220 thermal mass sustains intermittent overload without thermal shutdown.

Use Scenario: Isolated control of 120/240 VAC relays via optocoupler-driven base interface in PLC I/O modules.

IC Role / Device Role / Timing Role: High-voltage, high-current interface transistor translating logic signals to relay coil drive.

Use Value: -60 V V_CEO provides margin against line transients; low V_CE(sat) reduces self-heating during extended coil hold periods.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD54T4G	TO-252 (DPAK) package, lower P_D = 35 W, V_CEO = -60 V, h_FE = 500–1000	Suitable for surface-mount designs with moderate power density; not drop-in due to footprint and thermal interface differences	Select when PCB space constraints prohibit through-hole TO-220 and thermal load is ≤35 W
BDX54C	Higher V_CEO = -100 V, same TO-220 package and pinout, identical h_FE/V_CE(sat) specs	Used where higher voltage margin is required (e.g., 72 V battery systems), otherwise functionally interchangeable	Select when system transient voltage exceeds 60 V or long-term reliability under overvoltage stress is prioritized

Compared with MJD54T4G and BDX54C, the BDX54ATU offers optimal balance of through-hole manufacturability, 60 W thermal capability, and -60 V rating for 48 V industrial and audio applications - making it preferred where legacy TO-220 compatibility and proven field reliability are essential.

Availability

BDX54ATU is available at Aetrix Electronics and suitable for audio amplifier output stages, electromechanical hammer drivers, and industrial relay interfaces requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for BDX54ATU 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 (acquired Fairchild Semiconductor in 2016) is a global semiconductor supplier focused on energy-efficient electronics, with leadership in power management, analog, and discrete devices.

The BDX54ATU belongs to Fairchild's legacy BDX54 family of high-power PNP Darlington transistors, designed specifically for ruggedized linear and switching applications in industrial controls, audio systems, and electromechanical actuation.

FAQ

What is the maximum continuous collector current rating for BDX54ATU?

The BDX54ATU has a maximum continuous collector current (I_C) rating of -8 A at case temperature T_C = 25°C. This rating decreases with rising case temperature per the derating curve in the datasheet, reaching zero at approximately 150°C junction temperature. For reliable operation above 25°C, heatsinking must be sized accordingly - the BDX54ATU's TO-220 package enables direct thermal coupling to external heatsinks.

Does BDX54ATU include an integrated damper diode, and what is its forward voltage?

Yes, the BDX54ATU integrates a damper diode between collector and emitter. Its forward voltage (V_F) is -1.8 V at I_F = -3 A and -2.5 V at I_F = -8 A. This diode provides intrinsic flyback protection for inductive loads such as relays, solenoids, and hammer coils - eliminating the need for an external diode in most applications and improving layout simplicity and reliability.

What is the DC current gain (h_FE) specification for BDX54ATU, and under what conditions is it guaranteed?

The BDX54ATU guarantees a minimum DC current gain (h_FE) of 750 at V_CE = -3 V and I_C = -3 A. This high gain reduces required base drive current significantly compared to standard transistors, simplifying driver circuitry. The actual h_FE may exceed 1000 under light loads but degrades at higher currents and elevated temperatures - design margins should account for this variation.

Is BDX54ATU pin-compatible with other variants in the BDX54 family?

Yes, all BDX54 variants (BDX54, BDX54A, BDX54B, BDX54C) share identical TO-220 package, pinout (Base–Collector–Emitter), and mechanical dimensions. The only differences are absolute maximum voltage ratings: BDX54ATU is rated for -60 V V_CEO, while BDX54 is -45 V, BDX54B is -80 V, and BDX54C is -100 V. Electrical characteristics including h_FE, V_CE(sat), and diode VF are consistent across the family.

What is the safe operating area (SOA) limitation for BDX54ATU in pulsed operation?

The BDX54ATU supports pulsed collector current up to -12 A (I_CP) under specified test conditions (pulse width = 300 µs, duty cycle = 1.5%). Its SOA curve confirms capability up to 100 V and 10 A for 10 µs pulses, but continuous operation beyond -8 A or -60 V violates absolute maximum ratings. Designers must consult the published SOA graph to ensure transient conditions remain within the bounded region defined by second breakdown limits.

BDX54ATU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP - Darlington

Current - Collector (Ic) (Max):: 8 A

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

Vce Saturation (Max) @ Ib, Ic:: 2V @ 12mA, 3A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 3A, 3V

Power - Max:: 60 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BDX54ATU FAQ

1.How can I place an order for BDX54ATU through Aetrix?

Please submit a Request for Quotation (RFQ) for BDX54ATU 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 BDX54ATU reliable?

The price and inventory of BDX54ATU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BDX54ATU is usually 5 days.

3.What payment methods are accepted for BDX54ATU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BDX54ATU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BDX54ATU?

BDX54ATU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BDX54ATU 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 BDX54ATU?

For technical support, including BDX54ATU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BDX54ATU requirements.

6.How does Aetrix verify that BDX54ATU is sourced from the original manufacturer or authorized distributors?

All BDX54ATU 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 BDX54ATU meets industry standards.

7.What is the process for return or replacement of BDX54ATU?

All BDX54ATU units undergo pre-shipment inspection (PSI). If there is an issue with BDX54ATU, 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 BDX54ATU part is unused and in its original packaging.

Return procedure for BDX54ATU:

1.Submit a request within 90 days.

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

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