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onsemi KSE702STU
- Part No.:
- KSE702STU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
KSE702STU.pdf
- Description:
- TRANS PNP DARL 80V 4A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,358
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Product details
Overview
KSE702STU from Fairchild Semiconductor is a PNP epitaxial silicon Darlington transistor in TO-126 package, rated for -80 V VCEO, -4 A IC, and 40 W PC at TC=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 KSE702STU datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, monolithic Darlington architecture details, thermal derating behavior, safe operating area limits, and direct alternatives for industrial power interface design.
Technical Context
The KSE702STU implements a monolithic Darlington pair with integrated biasing resistors, enabling simplified drive requirements and stable DC current gain of ≥750 at IC = -1.5 A and -2.0 A. Its VCE(sat) is -2.5 V (max) under IC = -1.5 A / IB = -30 mA, and VBE(on) reaches -1.2 V under same conditions.
It operates within a junction temperature range of -55°C to +150°C, with power dissipation derated linearly above 25°C case temperature, and exhibits ICBO ≤ -500 µA at TC = 100°C - confirming robust leakage control in elevated-temperature environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -80 V - maximum collector-emitter voltage before breakdown; enables use in -80 V rail systems |
| IC | -4 A - continuous collector current rating; supports medium-power switching loads |
| PC | 40 W @ TC=25°C - thermal limit at heatsink interface; requires active cooling above ~75°C case temp |
| hFE | ≥750 @ IC=-1.5 A - high DC gain reduces required base drive current significantly |
| VCE(sat) | -2.5 V max @ IC=-1.5 A, IB=-30 mA - defines conduction loss and heat generation in saturated switch mode |
| R1 / R2 | ≈10 kΩ / ≈0.6 kΩ - internal base-emitter resistors enable self-biasing without external components |
Pinout & Package
Package: TO-126 - thermally robust through-hole plastic package with metal tab for heatsink mounting; pin 1 = Emitter, pin 2 = Collector, pin 3 = Base.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Current exit path for PNP Darlington | Connected to most positive rail in typical common-emitter configuration |
| 2 (Collector) | Main output current terminal | Drives load to ground or negative rail; electrically isolated from tab in standard TO-126 |
| 3 (Base) | Control input node | Accepts low-current drive due to internal resistor network; no external base resistor needed |
Key Features
| Feature | Design Value |
|---|---|
| Monolithic Darlington construction | Single-die integration eliminates inter-device mismatch and improves thermal tracking vs discrete pairs |
| Built-in base-emitter resistors | R1 ≈ 10 kΩ and R2 ≈ 0.6 kΩ reduce external component count and simplify PCB layout |
| High hFE ≥750 | Enables direct microcontroller GPIO driving without additional transistor stages |
| TO-126 package with metal tab | Provides mechanical stability and efficient thermal transfer to heatsink via screw-mount tab |
Applications
| Relay Driver Circuit | Linear Regulator Pass Element |
|---|---|
Use Scenario: Driving 12–24 V DC electromagnetic relays requiring >1 A coil current in industrial PLC output modules. IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current sinking capability with minimal base drive. Use Value: Built-in resistors eliminate need for external bias network; -80 V VCEO ensures margin against inductive kickback. | Use Scenario: Acting as series pass element in adjustable negative-output linear regulators delivering up to -3 A. IC Role / Device Role / Timing Role: High-gain current amplifier controlling output voltage via feedback loop. Use Value: hFE ≥750 allows precise regulation with low-error op-amp drive; TO-126 tab enables heatsinking for sustained 40 W dissipation. |
| DC Motor Speed Control | Power Supply Overcurrent Protection |
Use Scenario: Low-frequency PWM-controlled H-bridge half-bridge in 24 V battery-powered tools. IC Role / Device Role / Timing Role: High-side PNP switch regulating motor current direction and magnitude. Use Value: VCE(sat) ≤ -2.5 V minimizes conduction loss at 1.5 A; integrated R1/R2 simplifies gate-drive isolation. | Use Scenario: Current-sensing shunt amplifier stage combined with crowbar circuit in lab-grade bench supplies. IC Role / Device Role / Timing Role: Fast-turn-on Darlington triggering SCR-based overcurrent shutdown. Use Value: -100 µA ICEO at -80 V ensures reliable cutoff during fault detection; TO-126 thermal mass aids transient overload handling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP Darlington transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJE702 | Same VCEO (-80 V), identical TO-126 package, but hFE min = 750 only at IC = -2 A (not -1.5 A); no built-in resistors | Requires external base bias network; less suitable for low-base-drive microcontroller interfaces | Select when discrete bias control is preferred and higher IC operation dominates design |
| BDX53C | Higher VCEO (-100 V), same IC (-4 A), TO-126, no integrated resistors, hFE min = 750 @ IC = -3 A | Lacks internal R1/R2; better suited for high-voltage industrial controls where external bias tuning is acceptable | Choose for extended voltage margin and compatibility with legacy BDX-series designs |
Compared with MJE702 and BDX53C, the KSE702STU uniquely integrates base-emitter resistors to reduce component count and simplify drive, while maintaining identical -80 V/-4 A ratings and TO-126 thermal performance - making it optimal for space-constrained, low-complexity PNP switching.
Availability
KSE702STU is available at Aetrix Electronics and suitable for relay driver circuits, linear regulator pass elements, DC motor speed control, and power supply overcurrent protection requiring stable component supply across industrial OEM production cycles.
Supply support for KSE702STU 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 semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.
The KSE702STU belongs to Fairchild's legacy PNP Darlington transistor family designed for medium-power linear and switching applications where high DC gain, integrated biasing, and robust thermal packaging are essential.
FAQ
What is the maximum collector-emitter voltage rating for KSE702STU?
The KSE702STU has a maximum collector-emitter voltage (VCEO) rating of -80 V at TC = 25°C. This rating applies specifically to the KSE702 and KSE703 variants per the Fairchild datasheet Rev. A2. Operation beyond this voltage risks avalanche breakdown and permanent device failure. Derating is required at elevated temperatures per the published power derating curve.
Does KSE702STU include internal base-emitter resistors?
Yes, the KSE702STU features monolithic construction with two built-in base-emitter resistors: R1 ≈ 10 kΩ and R2 ≈ 0.6 kΩ. These resistors enable self-biasing and eliminate the need for external base resistors in many switching and linear applications. This distinguishes KSE702STU from non-resistor-equipped equivalents like MJE702.
What is the DC current gain (hFE) specification for KSE702STU?
The KSE702STU guarantees a minimum DC current gain (hFE) of 750 when tested at VCE = -3 V and IC = -1.5 A or -2.0 A. This high gain is enabled by its Darlington structure and internal resistor network. At IC = -4 A, hFE drops to a minimum of 100, as specified in the Fairchild datasheet.
Which package type does KSE702STU use, and how are its pins arranged?
The KSE702STU uses the TO-126 package with three leads: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base. The metal tab is electrically connected to the Collector and serves as a heatsink interface. This arrangement is confirmed in the mechanical drawings and pinout diagram of the Fairchild KSE700–703 datasheet Rev. A2.
Can KSE702STU be used as a direct replacement for KSE700 or KSE701?
No, KSE702STU is not a direct replacement for KSE700 or KSE701 due to differing voltage ratings: KSE700/701 have VCEO = -60 V, while KSE702STU is rated for -80 V. Although pin-compatible and functionally similar, substituting KSE702STU into a -60 V design may introduce unnecessary cost and thermal overhead, and using KSE700 in place of KSE702STU risks overvoltage failure in -80 V applications.
KSE702STU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Tube
- 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
KSE702STU FAQ
1.How can I place an order for KSE702STU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSE702STU 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 KSE702STU reliable?
The price and inventory of KSE702STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE702STU is usually 5 days.
3.What payment methods are accepted for KSE702STU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE702STU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSE702STU?
KSE702STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSE702STU 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 KSE702STU?
For technical support, including KSE702STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE702STU requirements.
6.How does Aetrix verify that KSE702STU is sourced from the original manufacturer or authorized distributors?
All KSE702STU 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 KSE702STU meets industry standards.
7.What is the process for return or replacement of KSE702STU?
All KSE702STU units undergo pre-shipment inspection (PSI). If there is an issue with KSE702STU, 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 KSE702STU part is unused and in its original packaging.
Return procedure for KSE702STU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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