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

onsemi BD538KTU

Name: BD538KTU
Brand: onsemi
SKU: BD538KTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD538KTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD538KTU.pdf

Description:: TRANS PNP 80V 8A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BD538KTU from Fairchild Semiconductor is a PNP epitaxial silicon power transistor in TO-220 package, rated for -80 V V_CEO, -8 A I_C, 50 W P_C, with h_FE ≥15 at I_C = -2 A and V_CE = -2 V, used in medium-power linear and switching applications such as DC motor control and power supply regulation.

For engineers reviewing the BD538KTU datasheet, pinout, applications, or equivalent options, key selection factors include its -80 V collector-emitter breakdown voltage, low -0.8 V V_CE(sat) at -2 A/-0.2 A drive, TO-220 thermal performance, complementary pairing with BD537, and suitability for industrial switching circuits requiring robust PNP gain and saturation behavior.

Technical Context

The BD538KTU operates as a medium-power PNP bipolar junction transistor optimized for linear amplification and hard-switching duty. Its design supports high-current DC operation up to -8 A with controlled saturation characteristics (V_CE(sat) ≤ -0.8 V) and stable DC current gain (h_FE = 15–40 depending on bias point), validated under pulsed test conditions (PW = 300 µs, duty cycle = 1.5%).

It features a maximum junction temperature of 150°C, storage range of -65°C to +150°C, and safe operating area defined across DC and pulse durations up to 10 ms. The device exhibits low leakage: ICBO ≤ -100 µA at V_CB = -80 V and ICES ≤ -100 µA at V_CE = -80 V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-80 V - Maximum allowable collector-emitter voltage before breakdown in common-emitter configuration
I_C (DC)	-8 A - Continuous collector current rating defining steady-state conduction capability
P_C	50 W - Maximum power dissipation at T_C = 25°C, requiring heatsinking for sustained operation
h_FE	15–40 - DC current gain range at V_CE = -2 V, critical for base drive sizing in switching designs
V_CE(sat)	-0.8 V - Collector-emitter saturation voltage at I_C = -2 A / I_B = -0.2 A, directly impacting conduction loss
f_T	3–12 MHz - Current gain bandwidth product indicating usable frequency limit for small-signal amplification

Pinout & Package

BD538KTU is housed in a standard TO-220 package with integral metal tab for heatsink mounting and electrical connection to collector. Pin assignment is fixed: Pin 1 = Base, Pin 2 = Collector (tab), Pin 3 = Emitter.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Base	Control terminal; requires negative current injection to turn on PNP device
Pin 2	Collector	Main high-current output terminal; electrically connected to metal tab for thermal and electrical path
Pin 3	Emitter	Current source terminal; typically tied to higher potential in PNP switch configurations

Key Features

Feature	Design Value
Low saturation voltage	V_CE(sat) ≤ -0.8 V at I_C = -2 A ensures minimal conduction loss in switching applications
High breakdown voltage	V_CEO = -80 V enables use in 48 V and 60 V industrial bus systems without derating
Complementary pairing	Designed as PNP counterpart to NPN BD537, supporting push-pull and H-bridge topologies
Thermal robustness	150°C max junction temperature and TO-220 package support continuous operation in ambient up to 80°C with proper heatsinking

Applications

DC Motor Control	Linear Voltage Regulator
Use Scenario: Bidirectional 24–48 V brushed DC motor driver in industrial actuators. IC Role / Device Role / Timing Role: PNP high-side switch controlling motor current flow during reverse polarity phase. Use Value: -80 V V_CEO and -8 A I_C allow direct interface with 48 V bus; low V_CE(sat) reduces heat generation during PWM on-time.	Use Scenario: Pass transistor in adjustable negative-output linear regulator (e.g., -5 V to -15 V). IC Role / Device Role / Timing Role: Series pass element regulating output by varying emitter-collector conduction. Use Value: Stable h_FE ≥15 at -2 A ensures predictable base drive requirements; 50 W P_C supports >3 W dissipation with heatsink.
Switched-Mode Power Supply	Industrial Relay Driver
Use Scenario: Main switch in low-frequency flyback or forward converter secondary-side synchronous rectification. IC Role / Device Role / Timing Role: PNP-controlled current sink in auxiliary winding-driven gate drive circuitry. Use Value: f_T ≥3 MHz supports reliable operation up to ~100 kHz switching; TO-220 thermal mass stabilizes transient thermal response.	Use Scenario: High-current relay coil driver in PLC I/O modules handling 24 V DC loads. IC Role / Device Role / Timing Role: Saturated switch providing full coil current to energize industrial relays (e.g., 1–2 A coils). Use Value: -0.8 V V_CE(sat) minimizes voltage drop across transistor, ensuring >23 V reaches relay coil for reliable pull-in.

DC Motor Control

Linear Voltage Regulator

Use Scenario: Bidirectional 24–48 V brushed DC motor driver in industrial actuators.

IC Role / Device Role / Timing Role: PNP high-side switch controlling motor current flow during reverse polarity phase.

Use Value: -80 V V_CEO and -8 A I_C allow direct interface with 48 V bus; low V_CE(sat) reduces heat generation during PWM on-time.

Use Scenario: Pass transistor in adjustable negative-output linear regulator (e.g., -5 V to -15 V).

IC Role / Device Role / Timing Role: Series pass element regulating output by varying emitter-collector conduction.

Use Value: Stable h_FE ≥15 at -2 A ensures predictable base drive requirements; 50 W P_C supports >3 W dissipation with heatsink.

Switched-Mode Power Supply

Industrial Relay Driver

Use Scenario: Main switch in low-frequency flyback or forward converter secondary-side synchronous rectification.

IC Role / Device Role / Timing Role: PNP-controlled current sink in auxiliary winding-driven gate drive circuitry.

Use Value: f_T ≥3 MHz supports reliable operation up to ~100 kHz switching; TO-220 thermal mass stabilizes transient thermal response.

Use Scenario: High-current relay coil driver in PLC I/O modules handling 24 V DC loads.

IC Role / Device Role / Timing Role: Saturated switch providing full coil current to energize industrial relays (e.g., 1–2 A coils).

Use Value: -0.8 V V_CE(sat) minimizes voltage drop across transistor, ensuring >23 V reaches relay coil for reliable pull-in.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD538G	TO-263 surface-mount package; identical V_CEO (-80 V), I_C (-8 A), but lower P_C (35 W @ T_C = 25°C)	Suitable for space-constrained PCBs where thermal management uses copper pour instead of external heatsink	Select MJD538G when board-level thermal design favors SMT layout and peak power is <35 W
BD538	Same die and specs, but in TO-220AB (non-isolated) variant; no insulated mounting hardware	Used where collector-to-heatsink isolation is not required, reducing mechanical assembly cost	Select BD538 when electrical isolation between collector and heatsink is unnecessary and cost optimization is prioritized

Compared with MJD538G and BD538, the BD538KTU provides full 50 W power dissipation in an insulated TO-220 package, making it optimal for high-reliability industrial switching where thermal margin and mounting safety are critical.

Availability

BD538KTU is available at Aetrix Electronics and suitable for DC motor control, linear voltage regulation, switched-mode power supply, and industrial relay driver applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for BD538KTU 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

Fairchild Semiconductor was a U.S.-based designer and manufacturer of analog and discrete semiconductors, acquired by ON Semiconductor in 2016; known for high-reliability power transistors and MOSFETs.

The BD538KTU belongs to Fairchild's BD53x PNP transistor family, engineered for medium-power linear and switching applications demanding high breakdown voltage, low saturation, and thermal stability in industrial environments.

FAQ

What is the maximum continuous collector current rating for BD538KTU?

The BD538KTU has a maximum continuous collector current (I_C) rating of -8 A at T_C = 25°C. This rating assumes adequate heatsinking; derating is required above 25°C case temperature per the power derating curve in the datasheet. Operation beyond this limit risks thermal runaway or permanent junction damage.

Is BD538KTU pin-compatible with BD537?

No, BD538KTU is not pin-compatible with BD537. BD537 is an NPN transistor with opposite pinout (Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base), while BD538KTU is PNP with Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter. They are complementary in function but require mirrored PCB layouts.

What is the typical DC current gain (h_FE) of BD538KTU at I_C = -2 A?

The BD538KTU exhibits h_FE ≥15 at V_CE = -2 V and I_C = -2 A, with typical values ranging up to 40 depending on h_FE group (J or K). This gain determines required base drive current-e.g., ≥50 mA base current needed for full -2 A collector conduction.

Does BD538KTU have built-in protection features like thermal shutdown?

No, BD538KTU is a discrete bipolar transistor without integrated protection circuitry. It relies entirely on external design measures-such as current-limiting resistors, heatsinking, and safe operating area (SOA) compliance-to prevent secondary breakdown, thermal runaway, or overvoltage failure.

Can BD538KTU be used in switching applications above 100 kHz?

BD538KTU is not recommended for switching above ~100 kHz. Its f_T is specified from 3–12 MHz, but practical hard-switching performance is limited by minority-carrier storage time and SOA constraints. For >100 kHz operation, consider RF-optimized or fast-switching transistors with documented switching times.

BD538KTU 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):: 8 A

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

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 600mA, 6A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 2A, 2V

Power - Max:: 50 W

Frequency - Transition:: 12MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BD538KTU FAQ

1.How can I place an order for BD538KTU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD538KTU 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 BD538KTU reliable?

The price and inventory of BD538KTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD538KTU is usually 5 days.

3.What payment methods are accepted for BD538KTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD538KTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD538KTU?

BD538KTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD538KTU 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 BD538KTU?

For technical support, including BD538KTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD538KTU requirements.

6.How does Aetrix verify that BD538KTU is sourced from the original manufacturer or authorized distributors?

All BD538KTU 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 BD538KTU meets industry standards.

7.What is the process for return or replacement of BD538KTU?

All BD538KTU units undergo pre-shipment inspection (PSI). If there is an issue with BD538KTU, 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 BD538KTU part is unused and in its original packaging.

Return procedure for BD538KTU:

1.Submit a request within 90 days.

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

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