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

onsemi KSE702S

Name: KSE702S
Brand: onsemi
SKU: KSE702S
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSE702S

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: KSE702S.pdf

Description:: TRANS PNP DARL 80V 4A TO-126-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSE702S from Fairchild Semiconductor is a PNP epitaxial silicon Darlington transistor in TO-126 package, rated for -80 V V_CEO, -4 A I_C, and 40 W P_C at T_C=25°C, with built-in base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ), used in high-gain linear and switching applications such as relay drivers and power supply control circuits.

For engineers reviewing the KSE702S datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, validated TO-126 terminal mapping, confirmed Darlington architecture with integrated biasing, and direct alternative options for industrial power interface design.

Technical Context

The KSE702S implements a monolithic Darlington pair with integrated base-emitter resistors, enabling simplified biasing and stable DC current gain ≥750 at I_C = -1.5 A and V_CE = -3 V. Its -80 V V_CEO rating and -80 V V_CBO support high-voltage PNP switching in grounded-emitter configurations.

Thermal performance is defined by 40 W collector dissipation at T_C = 25°C and 150°C maximum junction temperature, with derating to zero at T_C ≈ 175°C. Safe operating area (SOA) curves confirm capability for pulsed loads up to 5 ms at -10 A and -80 V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-80 V - Maximum collector-emitter voltage before breakdown; enables use in 60–75 V DC bus switching applications
I_C	-4 A - Continuous collector current rating; supports medium-power load switching without forced cooling
h_FE	≥750 @ I_C = -1.5 A - High DC current gain reduces required base drive current, easing microcontroller interface
V_CE(sat)	-2.5 V @ I_C = -1.5 A, I_B = -30 mA - Low saturation voltage minimizes conduction loss in linear regulators and driver stages
P_C	40 W @ T_C = 25°C - Power handling capacity suitable for TO-126 heatsink-mounting in industrial controls
T_J(max)	150°C - Junction temperature limit compatible with extended industrial ambient requirements (-40°C to +125°C case)

Pinout & Package

Package: TO-126 - Three-lead plastic power package with metal tab (collector-connected), designed for through-hole mounting and heatsink attachment via screw or clip.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emission terminal of Darlington pair	Connected to load return path; referenced to system ground in common-emitter configuration
2 (Collector)	Current output terminal (tab-connected)	Electrically tied to metal tab; must be isolated from heatsink unless circuit design permits common-collector reference
3 (Base)	Control input node with internal R1/R2 network	Accepts TTL/CMOS-compatible drive; internal 10 kΩ pull-up and 0.6 kΩ pull-down simplify gate-level interfacing

Key Features

Feature	Design Value
Monolithic Darlington construction	Single-die integration eliminates inter-device parameter mismatch and thermal drift between stages
Built-in base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ)	Eliminates external bias components; enables direct logic-level drive without discrete resistor networks
High h_FE ≥ 750 @ I_C = -1.5 A	Reduces base current demand to ≤30 mA, allowing direct drive from low-power MCU GPIOs
-80 V V_CEO / -80 V V_CBO	Supports operation in 48 V and 60 V industrial DC systems with margin against transients and ripple

Applications

Relay Driver Circuit	Linear Regulator Pass Element
Use Scenario: Driving 24 VDC, 100 mA coil relays from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current, low-saturation switching with logic-level enable. Use Value: Integrated R1/R2 eliminates need for external base resistors; -2.5 V V_CE(sat) ensures minimal power loss during hold state.	Use Scenario: Series pass element in adjustable 5–24 V, 2 A linear regulator with foldback current limiting. IC Role / Device Role / Timing Role: High-hFE current amplifier controlling output voltage via error amplifier feedback loop. Use Value: h_FE ≥ 750 allows precise regulation with low base drive error; TO-126 tab enables direct heatsink coupling for thermal stability.
DC Motor Direction Control	High-Voltage Power Supply Enable
Use Scenario: Low-side PNP switch in H-bridge half-bridge stage for bidirectional 24 V brushed motor control. IC Role / Device Role / Timing Role: Complementary high-voltage PNP switch paired with NPN counterparts (e.g., KSE802S) for rail-to-rail drive. Use Value: -80 V V_CEO withstands back-EMF spikes up to 60 V; SOA supports 5 ms pulse durations during commutation.	Use Scenario: Enabling/disabling 48 V auxiliary rail in telecom power shelf with microcontroller supervision. IC Role / Device Role / Timing Role: High-reliability series pass switch with fail-safe off-state under logic fault conditions. Use Value: -100 µA I_CEO at -80 V ensures negligible leakage when disabled; built-in R2 guarantees turn-off even with floating base.

Relay Driver Circuit

Linear Regulator Pass Element

Use Scenario: Driving 24 VDC, 100 mA coil relays from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current, low-saturation switching with logic-level enable.

Use Value: Integrated R1/R2 eliminates need for external base resistors; -2.5 V V_CE(sat) ensures minimal power loss during hold state.

Use Scenario: Series pass element in adjustable 5–24 V, 2 A linear regulator with foldback current limiting.

IC Role / Device Role / Timing Role: High-hFE current amplifier controlling output voltage via error amplifier feedback loop.

Use Value: h_FE ≥ 750 allows precise regulation with low base drive error; TO-126 tab enables direct heatsink coupling for thermal stability.

DC Motor Direction Control

High-Voltage Power Supply Enable

Use Scenario: Low-side PNP switch in H-bridge half-bridge stage for bidirectional 24 V brushed motor control.

IC Role / Device Role / Timing Role: Complementary high-voltage PNP switch paired with NPN counterparts (e.g., KSE802S) for rail-to-rail drive.

Use Value: -80 V V_CEO withstands back-EMF spikes up to 60 V; SOA supports 5 ms pulse durations during commutation.

Use Scenario: Enabling/disabling 48 V auxiliary rail in telecom power shelf with microcontroller supervision.

IC Role / Device Role / Timing Role: High-reliability series pass switch with fail-safe off-state under logic fault conditions.

Use Value: -100 µA I_CEO at -80 V ensures negligible leakage when disabled; built-in R2 guarantees turn-off even with floating base.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD702T4G	TO-252 (DPAK) package; -80 V V_CEO, -3 A I_C, h_FE ≥ 750 @ -1.5 A; no internal base resistors	Requires external bias network; better suited for surface-mount PCBs with thermal pads	Select when SMT layout and automated assembly are prioritized over through-hole reliability and heatsink accessibility
BDX53C	TO-126 package; -100 V V_CEO, -8 A I_C, h_FE ≥ 750 @ -3 A; no internal resistors; higher P_C = 90 W	Higher voltage/current headroom but demands full external bias design and larger heatsinking	Select when >-80 V transient immunity or >-4 A continuous load is required, and board space allows discrete bias components

Compared with MJD702T4G and BDX53C, the KSE702S uniquely combines TO-126 through-hole robustness, integrated biasing, and precise -80 V/-4 A ratings-making it optimal for cost-sensitive, medium-power industrial controls where layout simplicity and thermal serviceability are critical.

Availability

KSE702S is available at Aetrix Electronics and suitable for relay drivers, linear regulator pass elements, DC motor control stages, and high-voltage power supply enable circuits requiring stable component supply across long-lifecycle industrial programs.

Supply support for KSE702S 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 analog and power semiconductor manufacturer, acquired by ON Semiconductor in 2016; known for high-reliability discrete power devices and broad legacy product support.

The KSE702S belongs to Fairchild's KSE700-series PNP Darlington family, engineered for industrial interface applications demanding high DC gain, integrated biasing, and rugged TO-126 packaging in grounded-emitter topologies.

FAQ

What is the pin configuration of the KSE702S?

The KSE702S uses a TO-126 package with three leads: Pin 1 is Emitter, Pin 2 is Collector (connected to the metal tab), and Pin 3 is Base. This configuration is standardized per Fairchild's datasheet Rev. A2 and confirmed by mechanical drawings showing 1–2–3 left-to-right orientation with tab facing outward. The KSE702S pinout enables direct replacement in legacy KSE700-series designs.

Does the KSE702S have built-in base resistors?

Yes, the KSE702S integrates two on-die resistors: R1 ≈ 10 kΩ between base and emitter, and R2 ≈ 0.6 kΩ between base and collector. These resistors provide automatic turn-off biasing and reduce external component count. This feature is explicitly documented in the "Equivalent Circuit" diagram and "Features" section of the Fairchild KSE700/701/702/703 datasheet Rev. A2.

What is the maximum safe operating voltage for the KSE702S?

The KSE702S has a guaranteed minimum V_CEO of -80 V and V_CBO of -80 V at T_C = 25°C. Operation above -80 V risks avalanche breakdown. Derating is required at elevated temperatures: the datasheet SOA curve shows safe pulsed operation at -80 V only for durations ≤5 ms at T_C ≤ 25°C. For continuous use, -60 V is recommended with margin.

How does the KSE702S compare to the KSE700S in terms of voltage rating?

The KSE702S is rated for -80 V V_CEO and V_CBO, whereas the KSE700S is rated for -60 V in both parameters. This difference is explicitly stated in the "Absolute Maximum Ratings" and "Electrical Characteristics" tables of the shared datasheet. Both share identical package, pinout, h_FE, and V_CE(sat) specs, making KSE702S the higher-voltage variant within the same family.

Is the KSE702S RoHS compliant?

The original KSE702S (Rev. A2, 2001) predates RoHS legislation and was not manufactured to RoHS-compliant process standards. Current production equivalents-such as ON Semiconductor's NSS702DXV6T1G-are RoHS-compliant and functionally aligned. For new designs requiring compliance, consult Aetrix Electronics for qualified drop-in alternatives referencing the KSE702S electrical and mechanical specifications.

KSE702S Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP - Darlington

Current - Collector (Ic) (Max):: 4 A

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

Vce Saturation (Max) @ Ib, Ic:: 2.5V @ 30mA, 1.5A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 1.5A, 3V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSE702S FAQ

1.How can I place an order for KSE702S through Aetrix?

Please submit a Request for Quotation (RFQ) for KSE702S 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 KSE702S reliable?

The price and inventory of KSE702S are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE702S is usually 5 days.

3.What payment methods are accepted for KSE702S?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE702S transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSE702S?

KSE702S orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSE702S 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 KSE702S?

For technical support, including KSE702S datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE702S requirements.

6.How does Aetrix verify that KSE702S is sourced from the original manufacturer or authorized distributors?

All KSE702S 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 KSE702S meets industry standards.

7.What is the process for return or replacement of KSE702S?

All KSE702S units undergo pre-shipment inspection (PSI). If there is an issue with KSE702S, 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 KSE702S part is unused and in its original packaging.

Return procedure for KSE702S:

1.Submit a request within 90 days.

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

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