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

onsemi BC517_D26Z

Name: BC517_D26Z
Brand: onsemi
SKU: BC517_D26Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC517_D26Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: BC517_D26Z.pdf

Description:: TRANS NPN DARL 30V 1.2A TO-92-3

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Product details

Overview

BC517_D26Z from ON Semiconductor (formerly Fairchild) is an NPN Darlington transistor optimized for high-current-switching applications with DC current gain up to 30,000 at IC = 20 mA, VCE = 2.0 V, and collector-emitter breakdown voltage of 30 V. It supports continuous collector current up to 1.2 A and operates across –55 °C to +150 °C junction temperature range, commonly used in relay drivers and low-frequency power switching circuits.

For engineers reviewing the BC517_D26Z datasheet, pinout, applications, or equivalent options, key selection considerations include its Darlington configuration enabling ultra-high hFE, TO-92 package thermal limitations (RθJA = 200 °C/W), saturation voltage of 1.0 V at IC = 100 mA/IB = 0.1 mA, and absence of integrated base resistors.

Technical Context

The BC517_D26Z integrates two cascaded NPN transistors in a monolithic Darlington pair, delivering extremely high DC current gain while maintaining single-base control. Its structure requires external base current limiting and exhibits higher VBE(on) (1.4 V at IC = 10 mA) and VCE(sat) (1.0 V) compared to standard NPN transistors.

Designed for linear and switching operation below 100 kHz, it lacks built-in protection diodes or clamping, necessitating external flyback suppression in inductive load applications. Thermal derating begins above 25 °C at 5.0 mW/°C due to its 625 mW total dissipation rating in TO-92.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum safe collector-emitter voltage before breakdown under open-base conditions
h_FE	30,000 - Enables microampere-level base drive to switch 100 mA collector current
V_CE(sat)	1.0 V @ IC = 100 mA, IB = 0.1 mA - Higher saturation voltage than single NPN, increasing conduction loss
P_D	625 mW @ T_A = 25 °C - Limits usable continuous power in ambient-air mounting without heatsinking
R_θJA	200 °C/W - Requires careful thermal design; junction rises 200 °C per watt dissipated in still air
T_J Range	–55 °C to +150 °C - Supports industrial and automotive under-hood environments when thermally managed

Pinout & Package

Package: TO-92 - Standard through-hole plastic package with 3.60 mm body width, 4.58 mm height, and 1.27 mm lead pitch; suitable for manual assembly and wave soldering.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Main current output terminal	Connected to load return path; must handle full switched current up to 1.2 A
2 (Base)	Control input node	Receives low-current drive; no internal resistor - external series R required to limit IB
3 (Emitter)	Current return reference	Common emitter connection; voltage drop here affects overall circuit ground reference

Key Features

Feature	Design Value
Ultra-high DC current gain	h_FE = 30,000 enables µA-range base drive for 100 mA loads, reducing MCU GPIO burden
High collector current capability	IC = 1.2 A continuous allows direct driving of relays, solenoids, and small motors
Wide operating temperature range	–55 °C to +150 °C junction rating supports deployment in uncontrolled industrial enclosures
Low-cost TO-92 packaging	Standard footprint ensures compatibility with legacy PCBs and automated insertion equipment

Applications

Relay Driver Circuits	DC Motor Control (Low-Speed)
Use Scenario: Driving 12 V, 100 mA coil relays from microcontroller GPIO pins with limited drive strength. IC Role / Device Role / Timing Role: High-gain current amplifier translating logic-level signals into sufficient coil current. Use Value: Eliminates need for additional driver stages; single BC517_D26Z replaces discrete transistor pairs in space-constrained designs.	Use Scenario: Controlling bidirectional 24 V, 500 mA brushed DC motors in HVAC damper actuators. IC Role / Device Role / Timing Role: Low-frequency switching element in H-bridge half-bridge sections (with complementary PNP). Use Value: Delivers required stall current with minimal base drive overhead, simplifying gate-driver support circuitry.
LED Array Drivers	Industrial Sensor Interface
Use Scenario: Switching 1 A LED strings in emergency lighting systems using PWM dimming at <1 kHz. IC Role / Device Role / Timing Role: Constant-current switch operating in saturation region during ON state. Use Value: Maintains stable brightness across wide input voltage ranges due to high h_FE-stabilized current gain.	Use Scenario: Isolating and amplifying analog sensor outputs (e.g., thermistor networks) before ADC sampling. IC Role / Device Role / Timing Role: Emitter-follower buffer providing low-output-impedance signal conditioning. Use Value: Improves noise immunity and load-driving capability without requiring op-amp rail-to-rail output swing.

Relay Driver Circuits

DC Motor Control (Low-Speed)

Use Scenario: Driving 12 V, 100 mA coil relays from microcontroller GPIO pins with limited drive strength.

IC Role / Device Role / Timing Role: High-gain current amplifier translating logic-level signals into sufficient coil current.

Use Value: Eliminates need for additional driver stages; single BC517_D26Z replaces discrete transistor pairs in space-constrained designs.

Use Scenario: Controlling bidirectional 24 V, 500 mA brushed DC motors in HVAC damper actuators.

IC Role / Device Role / Timing Role: Low-frequency switching element in H-bridge half-bridge sections (with complementary PNP).

Use Value: Delivers required stall current with minimal base drive overhead, simplifying gate-driver support circuitry.

LED Array Drivers

Industrial Sensor Interface

Use Scenario: Switching 1 A LED strings in emergency lighting systems using PWM dimming at <1 kHz.

IC Role / Device Role / Timing Role: Constant-current switch operating in saturation region during ON state.

Use Value: Maintains stable brightness across wide input voltage ranges due to high h_FE-stabilized current gain.

Use Scenario: Isolating and amplifying analog sensor outputs (e.g., thermistor networks) before ADC sampling.

IC Role / Device Role / Timing Role: Emitter-follower buffer providing low-output-impedance signal conditioning.

Use Value: Improves noise immunity and load-driving capability without requiring op-amp rail-to-rail output swing.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ULN2003A	7-channel Darlington array with integrated base resistors and clamp diodes; SO-16 package	Designed for parallel digital I/O interfacing; not a single-transistor replacement	Select when driving multiple loads from logic outputs without external components
MPSA14	Slightly lower h_FE (10,000 min), same TO-92 package, V_CEO = 30 V, but lower P_D = 625 mW and R_θJA = 200 °C/W	Compatible pinout and basic specs; less gain margin for marginal base drive conditions	Choose when cost sensitivity outweighs need for maximum current gain stability

Compared with ULN2003A and MPSA14, the BC517_D26Z offers the highest guaranteed h_FE in a single-device TO-92 format, making it optimal for applications where base drive current is severely constrained and discrete layout is preferred over integrated arrays.

Availability

BC517_D26Z is available at Aetrix Electronics and suitable for relay drivers, LED array switches, industrial sensor interfaces, and low-speed DC motor controls requiring stable component supply and long-term industrial availability.

Supply support for BC517_D26Z 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 supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC517_D26Z belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, engineered for cost-sensitive, high-reliability discrete switching and amplification in non-automotive industrial systems.

FAQ

What is the maximum continuous collector current rating for BC517_D26Z?

The BC517_D26Z supports a maximum continuous collector current (IC) of 1.2 A at Ta = 25 °C, as specified in its Absolute Maximum Ratings table. Derating is required above 25 °C at 5.0 mW/°C, and actual usable current depends on PCB copper area, ambient airflow, and thermal interface. The BC517_D26Z must be operated within its safe operating area (SOA) curve to avoid secondary breakdown.

Does BC517_D26Z have an integrated base resistor?

No, the BC517_D26Z does not include an integrated base resistor. It is a bare Darlington transistor requiring an external series resistor to limit base current and ensure proper saturation. This differs from "digital transistor" variants like the NSD102BRT1G. Designers must calculate RB based on desired IB, V_BE(on) = 1.4 V, and drive voltage to avoid overdriving the base junction.

What is the typical VCE(sat) for BC517_D26Z under standard test conditions?

The BC517_D26Z exhibits a typical VCE(sat) of 1.0 V when tested at IC = 100 mA and IB = 0.1 mA. This value increases with higher collector current and decreases with increased base drive. At IC = 500 mA, VCE(sat) may rise to ~1.5 V, directly impacting power dissipation and efficiency in switching applications using BC517_D26Z.

Can BC517_D26Z be used in automotive applications?

The BC517_D26Z is not AEC-Q101 qualified and lacks automotive-grade screening or extended temperature validation beyond its rated –55 °C to +150 °C junction range. While its thermal specs permit under-hood use, ON Semiconductor does not endorse BC517_D26Z for safety-critical or life-support automotive functions. For such roles, consider AEC-Q101-certified alternatives like the NSS12201LT1G.

Is BC517_D26Z pin-compatible with BC547 or BC557?

No, BC517_D26Z is not pin-compatible with BC547 (NPN) or BC557 (PNP). Although all three use TO-92 packages, BC517_D26Z has Collector-Base-Emitter pinout (1-2-3), whereas BC547/BC557 follow Emitter-Base-Collector (1-2-3). Swapping them without board revision will cause functional failure or device damage. Always verify pin assignment using the official BC517_D26Z mechanical drawing.

BC517_D26Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 1.2 A

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 100µA, 100mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 30000 @ 20mA, 2V

Power - Max:: 625 mW

Frequency - Transition:: -

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC517_D26Z FAQ

1.How can I place an order for BC517_D26Z through Aetrix?

Please submit a Request for Quotation (RFQ) for BC517_D26Z 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 BC517_D26Z reliable?

The price and inventory of BC517_D26Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC517_D26Z is usually 5 days.

3.What payment methods are accepted for BC517_D26Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC517_D26Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC517_D26Z?

BC517_D26Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC517_D26Z 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 BC517_D26Z?

For technical support, including BC517_D26Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC517_D26Z requirements.

6.How does Aetrix verify that BC517_D26Z is sourced from the original manufacturer or authorized distributors?

All BC517_D26Z 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 BC517_D26Z meets industry standards.

7.What is the process for return or replacement of BC517_D26Z?

All BC517_D26Z units undergo pre-shipment inspection (PSI). If there is an issue with BC517_D26Z, 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 BC517_D26Z part is unused and in its original packaging.

Return procedure for BC517_D26Z:

1.Submit a request within 90 days.

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

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