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onsemi KSC5039FTU
- Part No.:
- KSC5039FTU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-220-3 Full Pack
- Datasheet:
-
KSC5039FTU.pdf
- Description:
- TRANS NPN 400V 5A TO-220F-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,248
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Product details
Overview
KSC5039FTU from ON Semiconductor (formerly Fairchild) is an NPN silicon power transistor designed for high-voltage switching applications, with 800 V collector-base breakdown voltage (BVCBO), 400 V collector-emitter breakdown voltage (BVCEO), and 5 A DC collector current rating. It operates in TO-220 package with base-collector-emitter pinout and is used in flyback converters, motor drive snubbers, and industrial relay drivers where robust voltage blocking and controlled turn-on/turn-off are required.
For engineers reviewing the KSC5039FTU datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, thermal limits, switching timing data, safe operating area boundaries, and real-world substitution guidance for high-voltage discrete BJT selection in power conversion and protection circuits.
Technical Context
The KSC5039FTU is a planar epitaxial NPN bipolar junction transistor optimized for high-voltage switching rather than linear amplification. Its 1.5 V VCE(sat) at IC = 2.5 A / IB = 0.5 A and 2.0 V VBE(sat) under same conditions indicate strong base drive efficiency, while 10 MHz fT supports moderate-speed switching up to ~100 kHz in hard-switched topologies.
Thermal design is constrained by 70 W collector dissipation at TC = 25°C and 150°C maximum junction temperature, requiring heatsinking for sustained >1 A operation. The device's 40 pF Cob at VCB = 10 V and 1 µs tON / 0.8 µs tF enable predictable gate-drive interface sizing in self-oscillating or externally triggered switch-mode designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCBO | 800 V - Withstands 800 V reverse bias between collector and base before breakdown; enables use in ≥600 V bus applications with margin. |
| VCEO | 400 V - Maximum sustainable collector-emitter voltage with base open; defines upper limit for flyback clamp or inductive load switching. |
| IC (DC) | 5 A - Continuous collector current capability; sets baseline conduction rating for thermal design and heatsink sizing. |
| VCE(sat) | 1.5 V @ IC = 2.5 A, IB = 0.5 A - Low saturation voltage reduces conduction loss and improves efficiency in hard-switched power stages. |
| fT | 10 MHz - Current gain bandwidth product; supports reliable switching up to ~100 kHz with adequate base drive strength. |
| tON / tF | 1 µs / 0.8 µs - Fast turn-on and fall times reduce switching losses and EMI generation in repetitive pulse applications. |
| Cob | 40 pF @ VCB = 10 V - Output capacitance impacts snubber design and switching speed; low value aids high-frequency operation. |
Pinout & Package
Package: TO-220 (3-lead, straight lead, insulated tab). Dimensions per Fairchild Rev. A: 15.90 mm × 10.08 mm × 4.50 mm, with 2.54 mm lead pitch and 3.60 mm mounting hole diameter.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Base) | Control input terminal | Receives forward base current to saturate the transistor; requires ≥0.5 A drive for full 2.5 A conduction. |
| 2 (Collector) | High-side current path | Connected to high-voltage rail or inductive load; carries full switched current and must be routed with creepage/clearance for 400+ V. |
| 3 (Emitter) | Low-side return path | Common reference node for base drive and load return; ties to ground or low-side switch in half-bridge configurations. |
Key Features
| Feature | Design Value |
|---|---|
| High voltage blocking | 800 V VCBO and 400 V VCEO enable direct use in 380 VAC rectified or 400 VDC bus systems with safety margin. |
| Low saturation loss | 1.5 V VCE(sat) at 2.5 A minimizes I²R conduction loss, reducing heatsink requirements in continuous-duty switching. |
| Fast switching | 1 µs turn-on and 0.8 µs fall time support efficient operation up to 100 kHz without excessive switching loss. |
| Robust SOA | DC and pulsed Safe Operating Area curves (Fig. 8–9) validate reliability under inductive load transients and repetitive overloads. |
| TO-220 mechanical standard | Industry-standard footprint and mounting allows drop-in replacement in existing PCB layouts using common heatsinks. |
Applications
| Switch-Mode Power Supply Snubber | Industrial Relay Driver |
|---|---|
Use Scenario: Absorbs voltage spikes during MOSFET/IGBT turn-off in flyback or forward converters. IC Role / Device Role / Timing Role: High-voltage NPN switch clamping transient energy into RC network; operates in pulsed saturation mode. Use Value: 400 V BVCEO and 10 A pulse rating allow reliable clamping of 300–350 V transients without secondary breakdown. | Use Scenario: Drives 24–48 VDC coil relays in PLC output modules with high isolation and surge immunity. IC Role / Device Role / Timing Role: Discrete power switch interfacing microcontroller GPIO to inductive relay load; handles back-EMF via built-in SOA margin. Use Value: 800 V VCBO withstands >600 V inductive kickback; 150°C TJ rating ensures stability in sealed industrial enclosures. |
| Motor Control Braking Circuit | High-Voltage Lamp Ballast |
Use Scenario: Provides dynamic braking path for brushed DC motors during rapid deceleration. IC Role / Device Role / Timing Role: High-current NPN switch shunting motor back-EMF into braking resistor; activated synchronously with H-bridge control. Use Value: 5 A DC rating and 70 W PC support sustained 3–4 A braking current; fast tF prevents shoot-through in bidirectional control. | Use Scenario: Controls preheat and run phases in electronic fluorescent lamp ballasts operating from 220–240 VAC mains. IC Role / Device Role / Timing Role: High-voltage series switch regulating lamp current in resonant LC topology; switches at 20–50 kHz. Use Value: 10 MHz fT and low Cob ensure stable oscillation and minimal phase shift across lamp life cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage NPN switching transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD127G | Lower VCBO (100 V), higher hFE (30–240), TO-263 package; not rated for >100 V blocking. | Suitable only for low-voltage (<100 V) switching; cannot replace KSC5039FTU in 400 V applications. | Select only if system voltage ≤80 V and surface-mount assembly is required. |
| BU508AF | Higher VCEO (1500 V), same TO-220 package, 7.5 A IC rating; slower tF (1.2 µs) and higher VCE(sat) (2.0 V). | Better for ultra-high-voltage flyback or CRT deflection; less efficient at 2–3 A due to higher saturation loss. | Prefer when >600 V blocking is mandatory; accept trade-off in conduction loss and switching speed. |
Compared with MJD127G and BU508AF, the KSC5039FTU delivers optimal balance of 400 V blocking, 5 A DC handling, 1.5 V VCE(sat), and 0.8 µs tF for cost-sensitive 200–400 V industrial switching-making it more efficient than BU508AF and far more voltage-capable than MJD127G.
Availability
KSC5039FTU is available at Aetrix Electronics and suitable for industrial motor drives, AC-DC power supplies, and high-reliability relay interface modules requiring stable component supply, long-lifecycle availability, and traceable sourcing from authorized channels.
Supply support for KSC5039FTU 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, high-performance silicon solutions for automotive, industrial, cloud computing, medical, and IoT applications.
The KSC5039FTU belongs to Fairchild's legacy high-voltage BJT portfolio, engineered specifically for ruggedized switching in offline power conversion, electromagnetic actuator control, and surge-tolerant industrial interfaces.
FAQ
What is the maximum continuous collector current for KSC5039FTU?
The KSC5039FTU has a maximum DC collector current (IC) rating of 5 A at TC = 25°C. Derating is required above 25°C case temperature per the power derating curve (Fig. 10), reaching zero dissipation at 150°C. For sustained 4 A operation, a heatsink maintaining TC ≤ 60°C is recommended based on its 70 W PC rating.
Does KSC5039FTU support pulse operation beyond its DC current rating?
Yes, the KSC5039FTU supports pulsed collector current up to 10 A (ICP) with PW = 300 µs and 2% duty cycle. This enables short-duration overload handling in motor startup or inrush limiting, provided peak junction temperature remains within 150°C and SOA limits (Fig. 8) are observed for each pulse width and voltage condition.
What is the base drive requirement to fully saturate KSC5039FTU?
To achieve specified VCE(sat) = 1.5 V at IC = 2.5 A, the KSC5039FTU requires IB = 0.5 A - corresponding to a forced beta (IC/IB) of 5. Driving with lower base current increases VCE(sat) nonlinearly; for example, IB = 0.25 A yields ~2.2 V VCE(sat), raising conduction loss significantly in high-duty-cycle applications.
Can KSC5039FTU be used in linear amplifier configurations?
No, the KSC5039FTU is optimized for switching operation, not linear amplification. Its hFE is specified only at VCE = 5 V and IC = 0.3 A (min 10), with no guaranteed gain linearity or thermal stability across collector voltage or current ranges. Use dedicated audio or precision BJTs (e.g., BC546, MMBT5551) for analog amplification.
Is KSC5039FTU RoHS compliant and halogen-free?
Yes, KSC5039FTU is RoHS compliant and halogen-free per ON Semiconductor's product change notices (PCN) for legacy Fairchild devices manufactured post-2010. The TO-220 package uses matte tin lead finish and Pb-free solderable terminations, meeting JEDEC J-STD-020 moisture sensitivity level 1 requirements.
KSC5039FTU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-3 Full Pack
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 5 A
- Voltage - Collector Emitter Breakdown (Max):
- 400 V
- Vce Saturation (Max) @ Ib, Ic:
- 1.5V @ 500mA, 2.5A
- Current - Collector Cutoff (Max):
- 10µA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 10 @ 300mA, 5V
- Power - Max:
- 30 W
- Frequency - Transition:
- 10MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220F-3
KSC5039FTU FAQ
1.How can I place an order for KSC5039FTU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC5039FTU 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 KSC5039FTU reliable?
The price and inventory of KSC5039FTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC5039FTU is usually 5 days.
3.What payment methods are accepted for KSC5039FTU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC5039FTU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC5039FTU?
KSC5039FTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC5039FTU 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 KSC5039FTU?
For technical support, including KSC5039FTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC5039FTU requirements.
6.How does Aetrix verify that KSC5039FTU is sourced from the original manufacturer or authorized distributors?
All KSC5039FTU 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 KSC5039FTU meets industry standards.
7.What is the process for return or replacement of KSC5039FTU?
All KSC5039FTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC5039FTU, 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 KSC5039FTU part is unused and in its original packaging.
Return procedure for KSC5039FTU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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