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

onsemi BDX34A

Name: BDX34A
Brand: onsemi
SKU: BDX34A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BDX34A

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BDX34A.pdf

Description:: TRANS PNP 60V 10A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BDX34A from ON Semiconductor is a PNP epitaxial silicon power transistor in TO-220 package, rated for -60 V V_CEO, -10 A continuous collector current, and 70 W power dissipation at T_C = 25°C. It serves as a high-gain Darlington switch in linear and switching power applications, including motor control and power supply regulation.

For engineers reviewing the BDX34A datasheet, pinout, applications, or equivalent options, key selection criteria include its -60 V blocking capability, minimum h_FE of 750 at -4 A, -2.5 V V_CE(sat), TO-220 thermal performance, and complementary pairing with BDX33A.

Technical Context

The BDX34A is a monolithic PNP Darlington transistor with integrated base-emitter shunt resistor, optimized for high-current switching and linear amplification. Its structure delivers high DC current gain (h_FE ≥ 750 at I_C = -4 A) while maintaining low saturation voltage (-2.5 V at I_C = -4 A, I_B = -8 mA).

It operates across -65°C to +150°C junction temperature range and supports pulsed collector current up to -15 A. The device is designed for use with external base drive and requires heatsinking under sustained load due to its 70 W P_C rating at T_C = 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-60 V - Maximum safe collector-emitter voltage before breakdown under open-base conditions
I_C (DC)	-10 A - Continuous collector current handling capacity with proper heatsinking
P_C	70 W - Maximum power dissipation at case temperature of 25°C; derates linearly above 25°C
h_FE	≥ 750 - Minimum DC current gain at V_CE = -3 V, I_C = -4 A, enabling low-base-drive switching
V_CE(sat)	-2.5 V - Collector-emitter voltage drop at I_C = -4 A and I_B = -8 mA, defining conduction loss
T_J	150°C - Maximum allowable junction temperature, limiting thermal design margin

Pinout & Package

BDX34A is housed in a through-hole TO-220 package with integral metal tab for heatsink mounting. Pin 1 is Base, Pin 2 is Collector (electrically connected to tab), and Pin 3 is Emitter.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Receives base current to turn on the Darlington pair; requires external current-limiting resistor
2 (Collector)	High-side power node	Electrically tied to metal tab; must be insulated from heatsink unless circuit common is collector
3 (Emitter)	Output reference	Serves as current return path; typically connected to system ground or load return in high-side switch configurations

Key Features

Feature	Design Value
High DC current gain	h_FE ≥ 750 at -4 A enables microcontroller-level base drive without additional pre-driver stages
Low saturation voltage	V_CE(sat) = -2.5 V at -4 A reduces conduction losses and heat generation in switching operation
Complementary pairing	Direct counterpart to BDX33A (NPN), simplifying push-pull and H-bridge design with matched voltage ratings
Robust safe operating area	SOA curve supports -10 A continuous and -15 A pulsed operation with appropriate thermal management

Applications

Motor Drive Circuits	Linear Power Supplies
Use Scenario: Driving brushed DC motors in industrial actuators requiring bidirectional control via H-bridge topology. IC Role / Device Role / Timing Role: High-side PNP Darlington switch providing current sinking path during active-low phase. Use Value: -60 V V_CEO and -10 A I_C support 48 V nominal bus systems with margin for inductive kickback suppression.	Use Scenario: Regulating output voltage in series-pass linear power supplies delivering up to 5 A. IC Role / Device Role / Timing Role: Pass transistor controlling current flow between unregulated input and regulated output rail. Use Value: High h_FE minimizes base drive requirements from error amplifier, reducing quiescent current overhead.
Relay Drivers	Overcurrent Protection Switches
Use Scenario: Replacing mechanical relays in programmable logic controller (PLC) output modules. IC Role / Device Role / Timing Role: Solid-state switch interfacing microcontroller GPIO to inductive relay coils. Use Value: Integrated Darlington structure eliminates need for external driver transistor, saving board space and component count.	Use Scenario: Implementing crowbar or foldback current limiting in battery charger circuits. IC Role / Device Role / Timing Role: Fast-acting series switch triggered by overcurrent comparator to disconnect load. Use Value: -2.5 V V_CE(sat) limits power dissipation during fault hold time, improving reliability under sustained overload.

Motor Drive Circuits

Linear Power Supplies

Use Scenario: Driving brushed DC motors in industrial actuators requiring bidirectional control via H-bridge topology.

IC Role / Device Role / Timing Role: High-side PNP Darlington switch providing current sinking path during active-low phase.

Use Value: -60 V V_CEO and -10 A I_C support 48 V nominal bus systems with margin for inductive kickback suppression.

Use Scenario: Regulating output voltage in series-pass linear power supplies delivering up to 5 A.

IC Role / Device Role / Timing Role: Pass transistor controlling current flow between unregulated input and regulated output rail.

Use Value: High h_FE minimizes base drive requirements from error amplifier, reducing quiescent current overhead.

Relay Drivers

Overcurrent Protection Switches

Use Scenario: Replacing mechanical relays in programmable logic controller (PLC) output modules.

IC Role / Device Role / Timing Role: Solid-state switch interfacing microcontroller GPIO to inductive relay coils.

Use Value: Integrated Darlington structure eliminates need for external driver transistor, saving board space and component count.

Use Scenario: Implementing crowbar or foldback current limiting in battery charger circuits.

IC Role / Device Role / Timing Role: Fast-acting series switch triggered by overcurrent comparator to disconnect load.

Use Value: -2.5 V V_CE(sat) limits power dissipation during fault hold time, improving reliability under sustained overload.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD32C	TO-252 (DPAK) surface-mount package; -100 V V_CEO; h_FE ≥ 500 at -3 A	Requires PCB rework for SMT assembly; higher voltage rating but lower gain and different thermal interface	Select when board space is constrained and automated assembly is required
BDX54A	Same TO-220 package; -60 V V_CEO; but NPN polarity and complementary to BDX34A	Not functionally interchangeable; used only in complementary pairs or NPN-side switching	Select only for NPN-side implementation in push-pull or complementary symmetry designs

Compared with MJD32C and BDX54A, the BDX34A offers through-hole TO-220 compatibility, verified -60 V/10 A capability, and guaranteed h_FE ≥ 750-making it optimal for legacy industrial controls where mechanical robustness and serviceability are prioritized over miniaturization.

Availability

BDX34A is available at Aetrix Electronics and suitable for motor drive circuits, linear power supplies, relay drivers, and overcurrent protection switches requiring stable component supply and long-lifecycle support.

Supply support for BDX34A 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 power management, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BDX34A belongs to ON Semiconductor's legacy power bipolar transistor family, originally developed by Fairchild and maintained for industrial replacement and repair applications where proven reliability and long-term availability are critical.

FAQ

What is the maximum continuous collector current rating for BDX34A?

The BDX34A is rated for -10 A continuous collector current (I_C) at case temperature T_C = 25°C with adequate heatsinking. Derating is required above 25°C per the published power derating curve; at T_C = 100°C, the usable I_C drops to approximately -5 A. This rating assumes proper PCB copper area and thermal interface to maintain junction temperature below 150°C.

Is BDX34A pin-compatible with BDX34 or BDX34B?

No, BDX34A is not pin-incompatible with BDX34 or BDX34B in terms of physical pinout-each shares identical TO-220 pin assignment (Base, Collector, Emitter). However, they differ electrically: BDX34A has -60 V V_CEO, while BDX34 is -45 V and BDX34B is -80 V. Substitution requires verification of voltage margin in the target circuit to avoid overstress.

Does BDX34A include an internal base-emitter resistor?

No, the BDX34A does not integrate a base-emitter resistor. It is a standard two-terminal base-input Darlington transistor. External base resistors must be used to limit drive current and ensure proper saturation. This differs from "digital transistors" like the NSBC114 series, which embed bias resistors internally.

What is the typical V_CE(sat) of BDX34A under standard test conditions?

The typical V_CE(sat) of BDX34A is -2.5 V at I_C = -4 A and I_B = -8 mA, as specified in the datasheet. This value reflects the combined saturation drop across both Darlington stages and defines conduction loss during fully turned-on operation. Designers should use the max value (-2.5 V) for worst-case thermal and efficiency calculations.

Can BDX34A be used in parallel for higher current handling?

BDX34A is not recommended for direct paralleling without individual emitter resistors or active current balancing. Variations in h_FE and V_BE between units can cause current hogging, leading to thermal runaway. If higher current is needed, consider using a single higher-rated device such as the MJ15003 or verify matched unit selection and thermal coupling per application note AN-1049.

BDX34A Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 10 A

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

Vce Saturation (Max) @ Ib, Ic:: 2.5V @ 8mA, 4A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 4A, 3V

Power - Max:: 70 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BDX34A FAQ

1.How can I place an order for BDX34A through Aetrix?

Please submit a Request for Quotation (RFQ) for BDX34A 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 BDX34A reliable?

The price and inventory of BDX34A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BDX34A is usually 5 days.

3.What payment methods are accepted for BDX34A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BDX34A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BDX34A?

BDX34A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BDX34A 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 BDX34A?

For technical support, including BDX34A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BDX34A requirements.

6.How does Aetrix verify that BDX34A is sourced from the original manufacturer or authorized distributors?

All BDX34A 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 BDX34A meets industry standards.

7.What is the process for return or replacement of BDX34A?

All BDX34A units undergo pre-shipment inspection (PSI). If there is an issue with BDX34A, 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 BDX34A part is unused and in its original packaging.

Return procedure for BDX34A:

1.Submit a request within 90 days.

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

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