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

STMicroelectronics BDX54C

Name: BDX54C
Brand: STMicroelectronics
SKU: BDX54C
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BDX54C

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BDX54C.pdf

Description:: TRANS PNP DARL 100V 8A TO-220

Quantity:: RFQ Add To RFQ list

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Inventory:4,005

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Product details

Overview

BDX54C from STMicroelectronics is a PNP complementary power Darlington transistor in TO-220 package, featuring V_CEO = 100 V, I_C = 8 A, h_FE ≥ 750 at 3 A, integrated antiparallel collector-emitter diode, and R₁ = 10 kΩ / R₂ = 150 Ω bias resistors - used in high-current linear audio output stages and industrial switching amplifiers.

For engineers reviewing the BDX54C datasheet, BDX54C pinout, BDX54C application, or BDX54C equivalent, key selection criteria include guaranteed DC current gain linearity, 100 V sustaining voltage under pulsed conditions, thermal resistance of 2.08 °C/W, and monolithic Darlington topology with built-in protection diode for inductive load commutation.

Technical Context

The BDX54C implements a monolithic PNP Darlington pair with on-die base-emitter resistors (R₁ = 10 kΩ, R₂ = 150 Ω) enabling direct TTL/CMOS drive without external bias networks. Its planar "base island" layout ensures stable h_FE linearity across collector current range.

It integrates an antiparallel emitter-collector diode (V_F = 1.8–2.5 V at 3–8 A), allowing safe flyback energy dissipation in inductive switching applications without discrete snubbers. Junction temperature is rated to 150 °C with 2.08 °C/W junction-to-case thermal resistance.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	100 V - Sustaining voltage at I_C = 100 mA, IB = 0 A; defines safe linear operating range for high-voltage audio and industrial loads.
I_C	8 A continuous - Maximum DC collector current; supports high-power Class AB output stages and motor driver half-bridges.
h_FE	≥750 at I_C = 3 A, V_CE = 3 V - High, linear DC gain enables low-base-drive-current operation in analog amplifiers.
R_thJC	2.08 °C/W - Enables 60 W power dissipation at T_C = 25 °C; requires heatsink design for sustained >20 W operation.
V_F (diode)	1.8–2.5 V at 3–8 A - Integrated antiparallel diode clamps inductive kickback; eliminates need for external freewheeling diode.
V_CE(sat)	≤2 V at I_C = 3 A, I_B = 12 mA - Low saturation voltage reduces conduction loss in switching applications.
T_J(max)	150 °C - Maximum junction temperature; sets thermal derating limit for reliability-critical industrial designs.

Pinout & Package

BDX54C uses TO-220 type A package with metal tab acting as collector terminal (pin 2). The plastic body isolates the tab electrically unless mounted with insulating hardware.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input node	Connected internally to R₁ (10 kΩ) and R₂ (150 Ω); accepts logic-level drive without external base resistor.
2 (Collector / TAB)	Main power output node	Metal tab is electrically connected to collector; must be insulated from heatsink unless circuit ground reference permits direct mounting.
3 (Emitter)	Power return path	Emitter is common reference for load; internal diode anode connects here, cathode to collector (pin 2).

Key Features

Feature	Design Value
Monolithic Darlington + integrated diode	Single-die integration eliminates interconnect parasitics and ensures matched thermal behavior between transistor and clamp diode.
On-chip bias resistors (R₁/R₂)	Eliminates external base drive components; enables direct interface with microcontrollers and logic ICs at ≤5 V.
High h_FE linearity	Stable gain across 0.5–6 A collector current range supports distortion-free audio amplification and precision current regulation.
100 V V_CEO(sus)	Guaranteed breakdown margin for 80 V rail systems; supports robust operation in unregulated industrial power supplies and transformer-coupled amplifiers.
Planar "base island" layout	Reduces second breakdown risk and improves safe operating area (SOA) versus epitaxial alternatives, critical for linear-mode operation.

Applications

Audio Power Amplifiers

Industrial Motor Drivers

Use Scenario: Output stage in 20–50 W Class AB audio amplifiers driving 4–8 Ω speakers.

IC Role / Device Role / Timing Role: PNP Darlington output transistor delivering high-current, low-distortion signal swing with minimal base drive.

Use Value: High h_FE linearity and integrated diode reduce crossover distortion and eliminate external flyback protection, simplifying PCB layout.

Use Scenario: High-side switch in 24–48 V DC motor H-bridge or solenoid control modules.

IC Role / Device Role / Timing Role: PNP Darlington providing low-saturation, high-current switching with built-in inductive load clamping.

Use Value: V_CE(sat) ≤2 V at 3 A and integrated diode enable efficient 100% duty-cycle operation without external snubbers.

Linear Voltage Regulators

Switch-Mode Power Supply (SMPS) Gate Drivers

Use Scenario: Pass element in adjustable 3–30 V, 5 A linear regulators for lab equipment and instrumentation.

IC Role / Device Role / Timing Role: Series pass transistor handling full load current while maintaining tight output voltage regulation.

Use Value: 150 °C T_J(max) and 2.08 °C/W R_thJC support thermally stable operation under worst-case dropout and ambient conditions.

Use Scenario: High-current gate driver for N-channel MOSFETs in 100 kHz–500 kHz SMPS half-bridge topologies.

IC Role / Device Role / Timing Role: PNP Darlington sourcing peak gate current (>3 A) during MOSFET turn-on transitions.

Use Value: Fast f_T and low V_CE(sat) minimize gate drive losses and improve switching efficiency at high frequencies.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11	V_CEO = 80 V (vs. 100 V), h_FE min = 1000, TO-263 package (surface-mount)	Limited to ≤80 V systems; requires PCB rework for SMT assembly vs. through-hole TO-220	Preferred where board space is constrained and voltage margin allows.
BDX54B	V_CEO = 80 V (vs. 100 V), otherwise identical pinout, package, and bias network	Not suitable for 100 V sustaining applications; obsolete per DS0845 Rev 5 (removed from ordering)	Select only if legacy design mandates 80 V rating and stock availability exists.

Compared with MJD44H11 and BDX54B, BDX54C provides superior 100 V ruggedness and through-hole manufacturability, making it optimal for new industrial amplifier and regulator designs requiring proven reliability and serviceable assembly.

Availability

BDX54C is available at Aetrix Electronics and suitable for audio power amplifiers, industrial motor drivers, linear voltage regulators, and SMPS gate drivers requiring stable component supply across multi-year production cycles.

Supply support for BDX54C 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

BDX54C belongs to ST's high-power bipolar transistor product line, engineered specifically for rugged linear and switching applications demanding high current gain, integrated protection, and thermal reliability in TO-220 form factor.

FAQ

Is BDX54C pin-compatible with BDX53C?

No - BDX54C is PNP while BDX53C is NPN; they share identical TO-220 pinout (Base–Collector–Emitter) but opposite polarity. Swapping them without circuit redesign causes immediate reverse-bias failure. They are complementary, not interchangeable.

Can BDX54C replace a standard PNP transistor like BC557 in high-power circuits?

No - BDX54C is a 8 A power Darlington with integrated resistors and diode; BC557 is a 100 mA small-signal transistor. Substitution would cause catastrophic overcurrent and thermal runaway due to mismatched current handling, gain, and thermal mass.

What is the function of the integrated antiparallel diode?

The integrated diode connects anode to emitter (pin 3) and cathode to collector (pin 2/tab). It conducts reverse current during inductive load turn-off, clamping voltage spikes and preventing transistor breakdown - eliminating need for external freewheeling diodes in relay/motor drivers.

Does BDX54C require external base resistors when driven by a microcontroller?

No - internal R₁ = 10 kΩ and R₂ = 150 Ω provide complete bias network. A 3.3 V or 5 V GPIO can directly connect to pin 1 (Base) to achieve full 3 A output current with ~12 mA base drive, verified per datasheet test condition.

BDX54C Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Active

Transistor Type:: PNP - Darlington

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

Voltage - Collector Emitter Breakdown (Max):: 100 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

BDX54C FAQ

1.How can I place an order for BDX54C through Aetrix?

Please submit a Request for Quotation (RFQ) for BDX54C 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 BDX54C reliable?

The price and inventory of BDX54C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BDX54C is usually 5 days.

3.What payment methods are accepted for BDX54C?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BDX54C transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BDX54C?

BDX54C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BDX54C 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 BDX54C?

For technical support, including BDX54C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BDX54C requirements.

6.How does Aetrix verify that BDX54C is sourced from the original manufacturer or authorized distributors?

All BDX54C 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 BDX54C meets industry standards.

7.What is the process for return or replacement of BDX54C?

All BDX54C units undergo pre-shipment inspection (PSI). If there is an issue with BDX54C, 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 BDX54C part is unused and in its original packaging.

Return procedure for BDX54C:

1.Submit a request within 90 days.

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

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