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

onsemi BDX34BG

Name: BDX34BG
Brand: onsemi
SKU: BDX34BG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BDX34BG

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BDX34BG.pdf

Description:: TRANS PNP DARL 80V 10A TO-220

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Product details

Overview

BDX34BG from onsemi is a PNP complementary Darlington power transistor in TO-220 package, rated for 10 A continuous collector current, 80 V collector-emitter sustaining voltage (V_CEO(sus)), and 70 W total device dissipation at T_C = 25°C; used in low-speed switching and linear regulator applications requiring high DC current gain (h_FE = 750 min at I_C = 3.0 A).

For engineers reviewing the BDX34BG datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, safe operating area limits, base-emitter shunt resistor integration, and RoHS-compliant Pb-free packaging details critical for industrial power control design.

Technical Context

The BDX34BG implements a monolithic Darlington pair with built-in base-emitter shunt resistors to ensure stable turn-off and reduce external component count. Its V_CE(sat) ≤ 2.5 V at I_C = 3.0 A and I_B = 6.0 mA enables efficient low-voltage switching in relay drivers and motor controls.

Thermal performance is defined by R_JC = 1.78°C/W and power derating of 0.56 W/°C above 25°C case temperature. Safe operating area (SOA) curves confirm second-breakdown-limited operation up to 100 µs pulses and thermally limited DC operation at T_C ≤ 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO(sus)	80 Vdc minimum - sustains 80 V across C–E at 100 mA with zero base drive, defining maximum off-state blocking capability
I_C (continuous)	10 Adc - supports sustained load currents up to 10 A without thermal runaway under proper heatsinking
P_D @ T_C = 25°C	70 W - maximum power dissipation achievable only with case held at 25°C; requires active cooling for full-rated current
h_FE	750 min at I_C = 3.0 A - enables low-base-drive switching (e.g., ~4 mA base current for 3 A collector load)
V_CE(sat)	2.5 V max at I_C = 3.0 A, I_B = 6.0 mA - sets conduction loss floor for efficiency-critical linear or saturated-switching use
T_J range	−65°C to +150°C - allows operation in automotive under-hood or industrial ambient environments with appropriate thermal design

Pinout & Package

BDX34BG uses the TO-220-3 (Case 221A, Style 1) package with 3 leads: Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter. The metal tab is electrically connected to the collector and serves as primary thermal path to heatsink.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Base)	Control input	Receives low-current drive signal; internal shunt resistor ensures reliable turn-off without external pull-down
Pin 2 (Collector)	High-current output node	Connected to metal tab; must be isolated from heatsink unless circuit design permits common-collector configuration
Pin 3 (Emitter)	Current return path	Serves as reference terminal for load; polarity defines PNP operation (current flows into emitter, out of collector)

Key Features

Feature	Design Value
Monolithic Darlington construction	Integrates driver and output transistors on single die, eliminating interconnect parasitics and ensuring matched thermal tracking
Built-in base-emitter shunt resistor	Guarantees turn-off even with open-base conditions; removes need for external base resistor in many switching circuits
RoHS-compliant Pb-free package	Meets EU Directive 2011/65/EU and JEDEC JS-001 standards; compatible with lead-free reflow and wave soldering processes
High V_CEO(sus) rating	80 V minimum blocking capability supports 24 V and 48 V industrial bus systems with margin against transients

Applications

DC Motor Control	Linear Voltage Regulator
Use Scenario: Driving brushed DC motors in industrial actuators with stall currents up to 8 A. IC Role / Device Role / Timing Role: PNP Darlington switch controlling motor direction and enable via base drive logic. Use Value: Low V_CE(sat) minimizes heat generation during PWM-on periods; built-in shunt resistor prevents unintended motor creep during microcontroller reset.	Use Scenario: High-current series pass element in adjustable 3–30 V, 5 A lab power supplies. IC Role / Device Role / Timing Role: Linear regulating transistor dissipating up to 45 W at 15 V dropout and 3 A load. Use Value: 70 W PD rating and 1.78°C/W R_JC allow stable operation with modest heatsinking; high h_FE reduces error amplifier drive burden.
Relay Driver	Overcurrent Protection Circuit
Use Scenario: Switching 24 VDC industrial relays with coil currents of 100–300 mA. IC Role / Device Role / Timing Role: High-gain interface between low-power logic and inductive relay load. Use Value: h_FE ≥ 750 enables direct drive from MCU GPIO (e.g., 3.3 V/20 mA output); V_CEO(sus) ≥ 80 V withstands 2× supply flyback spikes.	Use Scenario: Current-limiting element in battery charger protection modules limiting charge current to 6 A. IC Role / Device Role / Timing Role: Adjustable current-sense controlled pass device operating in linear region. Use Value: Precise V_CE(sat) specification enables accurate current sensing; SOA curve validates 100 ms overload tolerance at 12 A.

DC Motor Control

Linear Voltage Regulator

Use Scenario: Driving brushed DC motors in industrial actuators with stall currents up to 8 A.

IC Role / Device Role / Timing Role: PNP Darlington switch controlling motor direction and enable via base drive logic.

Use Value: Low V_CE(sat) minimizes heat generation during PWM-on periods; built-in shunt resistor prevents unintended motor creep during microcontroller reset.

Use Scenario: High-current series pass element in adjustable 3–30 V, 5 A lab power supplies.

IC Role / Device Role / Timing Role: Linear regulating transistor dissipating up to 45 W at 15 V dropout and 3 A load.

Use Value: 70 W PD rating and 1.78°C/W R_JC allow stable operation with modest heatsinking; high h_FE reduces error amplifier drive burden.

Relay Driver

Overcurrent Protection Circuit

Use Scenario: Switching 24 VDC industrial relays with coil currents of 100–300 mA.

IC Role / Device Role / Timing Role: High-gain interface between low-power logic and inductive relay load.

Use Value: h_FE ≥ 750 enables direct drive from MCU GPIO (e.g., 3.3 V/20 mA output); V_CEO(sus) ≥ 80 V withstands 2× supply flyback spikes.

Use Scenario: Current-limiting element in battery charger protection modules limiting charge current to 6 A.

IC Role / Device Role / Timing Role: Adjustable current-sense controlled pass device operating in linear region.

Use Value: Precise V_CE(sat) specification enables accurate current sensing; SOA curve validates 100 ms overload tolerance at 12 A.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11G	TO-263 package, 80 V V_CEO, 8 A I_C, no internal shunt resistor	Requires external base pull-down; better suited for surface-mount designs with space constraints	Select when PCB real estate is limited and thermal interface to heatsink is via soldered tab rather than mechanical clamp
BDX34C	Same TO-220 package but rated for 100 V V_CEO(sus); otherwise identical pinout and gain specs	Direct drop-in replacement where higher voltage margin is required (e.g., 72 V battery systems)	Choose BDX34C if system transients exceed 80 V or if future-proofing against voltage upgrades is needed

Compared with MJD44H11G, BDX34BG offers integrated turn-off assurance and through-hole mounting robustness; compared with BDX34C, it trades 20 V headroom for legacy compatibility and lower cost in 24–48 V applications.

Availability

BDX34BG is available at Aetrix Electronics and suitable for industrial motor control, linear power regulation, relay interfacing, and overcurrent protection circuits requiring stable component supply and long-term manufacturability support.

Supply support for BDX34BG 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BDX34BG belongs to the BDX33/BDX34 complementary Darlington family designed specifically for general-purpose, low-speed power switching in cost-sensitive industrial equipment where high DC gain and rugged TO-220 packaging are essential.

FAQ

What is the maximum continuous collector current rating for BDX34BG?

The BDX34BG is rated for 10 A continuous collector current (I_C) at case temperature T_C = 25°C. Operation at full current requires adequate heatsinking to maintain T_C ≤ 25°C; derating applies at higher temperatures per the 0.56 W/°C slope. At T_C = 100°C, maximum usable I_C drops to approximately 5.5 A based on thermal resistance and power limits. BDX34BG must not be operated beyond its SOA boundaries shown in Figure 2 of the official datasheet.

Does BDX34BG have an internal base-emitter shunt resistor?

Yes, the BDX34BG features monolithic construction with a built-in base-emitter shunt resistor, as explicitly stated in the "Features" section of the onsemi datasheet. This resistor ensures reliable turn-off even when the base drive is removed or floating, eliminating the need for an external pull-down resistor in most switching applications. This design trait distinguishes BDX34BG from discrete PNP transistors like the MJD44H11G, which lack integrated shunt components.

What is the collector-emitter saturation voltage V_CE(sat) for BDX34BG?

The BDX34BG has a maximum V_CE(sat) of 2.5 Vdc at I_C = 3.0 Adc and I_B = 6.0 mAdc, per the Electrical Characteristics table. This value represents worst-case conduction loss under specified test conditions and directly impacts power dissipation and efficiency in saturated-switching applications. Actual V_CE(sat) may be lower at reduced currents or temperatures, but design margins should use the 2.5 V maximum to ensure thermal stability in BDX34BG-based circuits.

Is BDX34BG RoHS compliant and lead-free?

Yes, BDX34BG is RoHS compliant and packaged in a Pb-free TO-220 format, as confirmed by the "MARKING DIAGRAM" and "ORDERING INFORMATION" sections of the onsemi datasheet. The "G" suffix in BDX34BG explicitly denotes Pb-free packaging, and the device meets EU Directive 2011/65/EU requirements. Soldering profiles must follow onsemi's Pb-free guidelines, including peak reflow temperatures up to 260°C for 10 seconds, as detailed in the SOLDERING AND MOUNTING TECHNIQUES REFERENCE MANUAL.

What is the thermal resistance junction-to-case (R_JC) for BDX34BG?

The BDX34BG has a thermal resistance of R_JC = 1.78°C/W, as specified in the "THERMAL CHARACTERISTICS" table. This value quantifies the temperature rise from junction to case per watt of dissipated power and is critical for heatsink sizing. When calculating required heatsink thermal resistance, subtract 1.78°C/W from the total allowable R_JA budget, assuming ideal mounting (e.g., thermal compound, flat surface contact). The BDX34BG's R_JC enables effective thermal management in compact industrial enclosures when paired with standard TO-220-compatible heatsinks.

BDX34BG 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):: 10 A

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

Vce Saturation (Max) @ Ib, Ic:: 2.5V @ 6mA, 3A

Current - Collector Cutoff (Max):: 500µA

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

Power - Max:: 70 W

Frequency - Transition:: -

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

BDX34BG FAQ

1.How can I place an order for BDX34BG through Aetrix?

Please submit a Request for Quotation (RFQ) for BDX34BG 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 BDX34BG reliable?

The price and inventory of BDX34BG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BDX34BG is usually 5 days.

3.What payment methods are accepted for BDX34BG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BDX34BG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BDX34BG?

BDX34BG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BDX34BG 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 BDX34BG?

For technical support, including BDX34BG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BDX34BG requirements.

6.How does Aetrix verify that BDX34BG is sourced from the original manufacturer or authorized distributors?

All BDX34BG 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 BDX34BG meets industry standards.

7.What is the process for return or replacement of BDX34BG?

All BDX34BG units undergo pre-shipment inspection (PSI). If there is an issue with BDX34BG, 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 BDX34BG part is unused and in its original packaging.

Return procedure for BDX34BG:

1.Submit a request within 90 days.

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

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