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onsemi KSE703STU
- Part No.:
- KSE703STU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
KSE703STU.pdf
- Description:
- TRANS PNP DARL 80V 4A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:6,744
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Product details
Overview
KSE703STU from Fairchild Semiconductor is a PNP epitaxial silicon Darlington transistor in TO-126 package, rated for -80 V VCEO, -4 A IC, 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 error amplifiers.
For engineers reviewing the KSE703STU datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed hFE ≥ 750 at IC = -2 A, VCE(sat) ≤ -2.8 V at IC = -2 A / IB = -40 mA, and monolithic construction with integrated biasing resistors enabling simplified driver-stage design.
Technical Context
The KSE703STU implements a monolithic Darlington pair with integrated base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ), eliminating external bias components. It delivers high DC current gain (hFE ≥ 750 at IC = -2 A) while maintaining low saturation voltage (VCE(sat) ≤ -2.8 V under specified drive conditions).
Designed for medium-power linear and switching operation, it supports safe operating area (SOA) up to 5 ms at VCE = -40 V and IC = -2 A, with junction temperature rated to 150°C and thermal derating beginning at TC > 25°C per the published power derating curve.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -80 V - Maximum collector-emitter voltage before breakdown; defines usable voltage headroom in high-side switch or amplifier output stage |
| IC | -4 A - Continuous collector current rating; sets maximum load-handling capability in relay or motor driver circuits |
| PC @ TC=25°C | 40 W - Maximum dissipated power at case temperature 25°C; requires heatsinking for sustained operation above ~10 W |
| hFE | ≥750 @ IC = -2 A - High DC current gain enables low-base-drive-current operation, reducing driver-stage complexity |
| VCE(sat) | ≤ -2.8 V @ IC = -2 A, IB = -40 mA - Low saturation voltage minimizes conduction loss and heat generation in switching applications |
| R1 / R2 | ≈10 kΩ / ≈0.6 kΩ - Integrated base-emitter resistors provide self-biasing, eliminating need for external base resistor network |
Pinout & Package
Package: TO-126, 3-lead plastic power package with emitter (pin 1), collector (pin 2), and base (pin 3) terminals; mounting tab is electrically connected to collector.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Emitter terminal of Darlington pair | Common reference node for input signal; polarity defines PNP operation and current sink behavior |
| 2 (Collector) | Collector terminal of Darlington pair | Connected to mounting tab; serves as high-current output node and primary heat path to heatsink |
| 3 (Base) | Input control terminal with internal bias network | Driven by logic-level or analog signal; internal R1/R2 enable single-resistor drive and prevent unintended turn-on |
Key Features
| Feature | Design Value |
|---|---|
| Monolithic Darlington with integrated bias resistors | Eliminates external base resistor network, reduces BOM count, and improves layout reliability in space-constrained designs |
| Guaranteed hFE ≥ 750 at IC = -2 A | Enables robust switching with low base drive current (e.g., < 40 mA), compatible with microcontroller GPIO or op-amp outputs |
| VCE(sat) ≤ -2.8 V at rated IC/IB | Reduces conduction loss and thermal stress compared to standard PNP transistors, extending safe operating time in pulsed loads |
| TO-126 package with collector-connected tab | Provides direct thermal path to heatsink and mechanical stability for medium-power board-level mounting |
Applications
| Relay Driver Stage | Linear Regulator Error Amplifier |
|---|---|
Use Scenario: Driving 12 V/24 V electromagnetic relays in industrial PLC output modules. IC Role / Device Role / Timing Role: PNP Darlington switch sinking relay coil current with high gain and low saturation loss. Use Value: Enables direct microcontroller GPIO drive without external base resistor; VCE(sat) ≤ -2.8 V ensures minimal power loss and coil voltage drop. | Use Scenario: Output stage of adjustable linear regulator feedback loop (e.g., LM317-based design). IC Role / Device Role / Timing Role: High-gain current amplifier correcting output voltage error via pass transistor base control. Use Value: hFE ≥ 750 allows precise regulation with low-error-signal current, improving load transient response and line regulation. |
| DC Motor Direction Control (Low-Side) | High-Voltage Signal Inverter |
Use Scenario: Low-side switching in bidirectional H-bridge half-bridge section for 24 V brushed DC motors. IC Role / Device Role / Timing Role: Complementary PNP switch paired with NPN counterpart for direction reversal and braking. Use Value: -80 V VCEO rating provides margin against inductive kickback; SOA supports 5 ms pulse handling during motor commutation. | Use Scenario: Level-shifting inverter for interfacing 3.3 V logic to -48 V telecom signaling lines. IC Role / Device Role / Timing Role: High-voltage PNP inverter stage translating logic states into negative rail-referenced signals. Use Value: -80 V VCBO and -5 V VEBO ensure reliable operation across wide common-mode swing without breakdown or leakage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP Darlington transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD703T4G | TO-220 package; identical VCEO (-80 V), IC (-4 A), but hFE min = 1000 @ IC = -2 A; no integrated bias resistors | Requires external base resistor network; better suited for precision biasing or higher-speed switching where R1/R2 introduce delay | Select when higher hFE and discrete bias control are prioritized over component count reduction |
| KSD703 | Same TO-126 package and pinout; identical electrical specs except VCEO = -60 V (vs. -80 V); same R1/R2 values | Limited to ≤60 V systems; unsuitable for 72 V battery or telecom -48 V with margin | Select only for cost-sensitive 60 V-class designs where voltage margin is not required |
Compared with MJD703T4G and KSD703, the KSE703STU uniquely combines TO-126 form factor, -80 V rating, and monolithic bias resistors-enabling compact, low-component-count PNP switching where layout simplicity and voltage margin are critical.
Availability
KSE703STU is available at Aetrix Electronics and suitable for relay drivers, linear regulator error amplifiers, DC motor control stages, and high-voltage inverters requiring stable component supply and long-term industrial availability.
Supply support for KSE703STU 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, acquired by ON Semiconductor in 2016.
The KSE703STU belongs to Fairchild's legacy high-gain PNP Darlington family, designed for industrial control, power supply feedback, and electromechanical interface applications requiring simplified biasing and robust medium-power switching.
FAQ
What is the maximum collector-emitter voltage rating for the KSE703STU?
The KSE703STU has a guaranteed VCEO rating of -80 V at TC = 25°C. This rating applies under open-base conditions and defines the absolute maximum reverse voltage the device can withstand between collector and emitter without breakdown. Operation above this value risks permanent damage. Derating is required at elevated case temperatures per the published power derating curve.
Does the KSE703STU require an external base resistor?
No, the KSE703STU does not require an external base resistor because it integrates two on-die resistors: R1 ≈ 10 kΩ between base and emitter, and R2 ≈ 0.6 kΩ between base and collector. These provide self-biasing and prevent unintended turn-on due to leakage currents, simplifying circuit design and reducing component count in driver applications.
What is the DC current gain (hFE) specification for the KSE703STU?
The KSE703STU guarantees hFE ≥ 750 at VCE = -3 V and IC = -2 A. This minimum gain is specified for the KSE701/KSE703 variants and reflects its Darlington configuration. At IC = -4 A, hFE drops to ≥100, which remains sufficient for most switching applications requiring moderate drive efficiency.
Is the KSE703STU pin-compatible with other devices in the KSE700 series?
Yes, the KSE703STU shares the same TO-126 package and pinout (Emitter–Collector–Base) with all KSE700-series devices, including KSE700, KSE701, KSE702, and KSE703. However, voltage ratings differ: KSE700/KSE701 are rated for -60 V VCEO, while KSE702/KSE703 are rated for -80 V. Electrical substitution requires verifying voltage margin requirements.
What thermal considerations apply to the KSE703STU in continuous operation?
The KSE703STU has a maximum junction temperature of 150°C and a case-to-ambient thermal resistance (RθJA) of approximately 2.5°C/W in typical TO-126 mounting. At full 40 W dissipation, even with ideal heatsinking, junction temperature rises rapidly-so continuous operation above ~10–15 W requires active cooling or derating. The published power derating curve shows linear reduction starting at TC > 25°C.
KSE703STU 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:
- 2.8V @ 40mA, 2A
- Current - Collector Cutoff (Max):
- 100µA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 750 @ 2A, 3V
- Power - Max:
- 40 W
- Frequency - Transition:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
KSE703STU FAQ
1.How can I place an order for KSE703STU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSE703STU 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 KSE703STU reliable?
The price and inventory of KSE703STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE703STU is usually 5 days.
3.What payment methods are accepted for KSE703STU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE703STU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSE703STU?
KSE703STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSE703STU 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 KSE703STU?
For technical support, including KSE703STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE703STU requirements.
6.How does Aetrix verify that KSE703STU is sourced from the original manufacturer or authorized distributors?
All KSE703STU 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 KSE703STU meets industry standards.
7.What is the process for return or replacement of KSE703STU?
All KSE703STU units undergo pre-shipment inspection (PSI). If there is an issue with KSE703STU, 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 KSE703STU part is unused and in its original packaging.
Return procedure for KSE703STU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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