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onsemi KSC3953CSTU
- Part No.:
- KSC3953CSTU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
KSC3953CSTU.pdf
- Description:
- TRANS NPN 120V 0.2A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,742
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Product details
Overview
KSC3953CSTU from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for CRT display video output stages, featuring VCEO = 120 V, IC = 200 mA (DC), fT = 400 MHz (typ.), Cre = 1.7 pF (typ.), and TO-126 package with emitter-collector-base pinout.
For engineers reviewing the KSC3953CSTU datasheet, pinout, applications, or equivalent options, this device serves as a high-voltage, high-frequency switching transistor where low reverse transfer capacitance and stable DC current gain across operating current are critical for video signal fidelity and thermal reliability in analog display driver circuits.
Technical Context
This NPN transistor operates with a 120 V collector-emitter breakdown voltage and supports pulsed collector currents up to 400 mA, enabling robust video output stage switching under transient load conditions. Its 400 MHz current gain bandwidth product and 1.7 pF reverse transfer capacitance ensure minimal signal distortion at high frequencies typical of CRT horizontal deflection and video amplification.
The device exhibits hFE = 40–80 (Class C) at IC = 10 mA and hFE = 20–120 (Class C) at IC = 100 mA, with VCE(sat) = 1.0 V at IC = 30 mA/IB = 3 mA - confirming suitability for saturated-switching applications requiring low on-state loss and fast turn-off response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 120 V - enables use in CRT video output stages with high-voltage sweep and flyback coupling |
| fT | 400 MHz (typ.) - supports wideband video signal amplification without phase degradation |
| Cre | 1.7 pF (typ.) - minimizes feedback-induced instability and ringing in high-gain video amplifiers |
| hFE (IC=10mA) | 40–80 (Class C) - provides predictable DC bias stability in fixed-gain video driver designs |
| PC (TC=25°C) | 8 W - allows high-power dissipation when mounted on heatsink, critical for continuous video output operation |
| VCE(sat) | 1.0 V @ IC=30mA/IB=3mA - ensures low conduction loss and reduced thermal stress during saturation |
Pinout & Package
Package: TO-126 - molded plastic power package with integral heat slug, 3-pin through-hole mounting, 16.10 mm × 13.06 mm footprint, 14.20 mm max height, suitable for manual or wave solder assembly and board-level thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Reference node for current return path; connected to ground or cathode return in CRT video output stage |
| 2 | Collector | Main power output node; interfaces directly with CRT anode supply or horizontal deflection transformer primary |
| 3 | Base | Control input for current amplification; driven by preceding video preamplifier or pulse generator stage |
Key Features
| Feature | Design Value |
|---|---|
| High fT bandwidth | 400 MHz typical - preserves rise/fall time integrity of composite video signals up to ~50 MHz fundamental content |
| Low Cre capacitance | 1.7 pF typical - reduces Miller-effect feedback, improving amplifier stability and reducing overshoot in video drivers |
| High VCEO rating | 120 V - accommodates CRT anode voltage transients and flyback spikes without breakdown |
| Class C hFE binning | 40–80 @ 10 mA - enables consistent gain matching across production units in multi-channel CRT video outputs |
Applications
| CRT Video Output Stage | Horizontal Deflection Driver |
|---|---|
Use Scenario: Amplifying composite video signals before CRT cathode modulation in analog monitors and TVs. IC Role / Device Role / Timing Role: Final-stage NPN switch/amplifier delivering high-voltage, high-slew-rate video current to CRT cathode. Use Value: 120 V VCEO and 400 MHz fT maintain signal fidelity and edge sharpness across full video bandwidth. | Use Scenario: Switching horizontal deflection yoke current in CRT scan circuitry. IC Role / Device Role / Timing Role: High-current, high-voltage switching transistor in flyback-timed horizontal output stage. Use Value: 8 W PC (TC=25°C) and 400 mA ICP support repetitive high-energy pulse delivery without thermal runaway. |
| Video Signal Buffer | Analog Monitor Power Supply Control |
Use Scenario: Isolating and buffering RGB or sync signals between video processor and CRT driver ICs. IC Role / Device Role / Timing Role: Unity-gain emitter-follower buffer with low output impedance and high linearity. Use Value: Low VCE(sat) = 1.0 V and stable hFE ensure minimal DC offset and gain variation across temperature. | Use Scenario: Regulating auxiliary high-voltage supplies (e.g., focus/screen grids) in CRT monitor SMPS feedback paths. IC Role / Device Role / Timing Role: Linear pass transistor in high-voltage error amplifier output stage. Use Value: 150 °C TJ rating and 120 V BVCBO allow safe operation under sustained high-VCE bias conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN high-voltage, high-frequency transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD127G | VCEO = 100 V (vs. 120 V); fT = 30 MHz (vs. 400 MHz); TO-220 package | Limited to lower-frequency power switching; unsuitable for CRT video bandwidth | Select only if voltage margin >20 V is not required and bandwidth demand is <5 MHz |
| KSC2690A | VCEO = 120 V; fT = 120 MHz (vs. 400 MHz); hFE = 60–120 (Class D); TO-126 | Lower bandwidth restricts use to baseband video or deflection timing, not RF-rich video signals | Acceptable for non-critical CRT auxiliary stages where 400 MHz fT is not needed |
Compared with MJD127G and KSC2690A, the KSC3953CSTU delivers uniquely high fT and low Cre within the TO-126 form factor - making it irreplaceable for CRT video output stages demanding both 120 V standoff and >100 MHz signal integrity.
Availability
KSC3953CSTU is available at Aetrix Electronics and suitable for CRT display video output stages, horizontal deflection drivers, and analog monitor power supply control circuits requiring stable component supply and long-lifecycle availability.
Supply support for KSC3953CSTU 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 manufacturer specializing in power discrete devices, analog ICs, and interface solutions before its acquisition by ON Semiconductor in 2016.
The KSC3953CSTU belongs to Fairchild's legacy high-voltage NPN transistor family, engineered specifically for analog video signal amplification and switching in CRT-based display systems.
FAQ
What is the maximum collector-emitter voltage rating for KSC3953CSTU?
The KSC3953CSTU has a maximum collector-emitter voltage (VCEO) rating of 120 V at TC = 25°C. This specification is verified per the Fairchild Rev. A datasheet and defines the upper limit of DC or pulse voltage the device can sustain between collector and emitter with base open, making it suitable for CRT video output and horizontal deflection applications where flyback transients exceed 100 V. Exceeding this rating risks junction breakdown.
What does the 'C' suffix in KSC3953CSTU indicate?
The 'C' in KSC3953CSTU denotes the hFE gain classification bin: for KSC3953CSTU, hFE ranges from 40 to 80 at IC = 10 mA and VCE = 10 V. This binning ensures predictable DC current gain in production units, supporting consistent biasing in CRT video output stages. The 'STU' suffix indicates TO-126 packaging with standard lead finish and tape-and-reel shipping configuration.
Is KSC3953CSTU suitable for linear amplifier applications?
Yes, KSC3953CSTU is suitable for linear amplifier applications such as CRT video output buffers, provided operating conditions remain within its Safe Operating Area (SOA). Its 400 MHz fT, low Cre (1.7 pF), and stable hFE across IC = 1–100 mA support high-fidelity analog amplification. However, thermal design must account for its 8 W PC (TC = 25°C) limit and derating above 25°C case temperature.
What is the pin configuration of KSC3953CSTU in the TO-126 package?
The KSC3953CSTU uses a standard TO-126 pinout: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base - with the flat side of the package facing the viewer and leads downward. This configuration is confirmed in the Fairchild Rev. A datasheet mechanical drawing and matches industry-standard TO-126 orientation for PCB layout and heatsink mounting compatibility.
How does KSC3953CSTU compare to KSC2690A in video applications?
KSC3953CSTU offers 400 MHz fT versus KSC2690A's 120 MHz fT and lower Cre (1.7 pF vs. ~3.5 pF), giving it superior high-frequency response and stability in CRT video output stages. While both share 120 V VCEO and TO-126 packaging, KSC3953CSTU's higher bandwidth makes it preferred for full-bandwidth composite video amplification where edge sharpness and minimal phase shift are critical.
KSC3953CSTU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 200 mA
- Voltage - Collector Emitter Breakdown (Max):
- 120 V
- Vce Saturation (Max) @ Ib, Ic:
- 1V @ 3mA, 30mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 40 @ 10mA, 10V
- Power - Max:
- 1.3 W
- Frequency - Transition:
- 400MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
KSC3953CSTU FAQ
1.How can I place an order for KSC3953CSTU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC3953CSTU 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 KSC3953CSTU reliable?
The price and inventory of KSC3953CSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC3953CSTU is usually 5 days.
3.What payment methods are accepted for KSC3953CSTU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC3953CSTU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC3953CSTU?
KSC3953CSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC3953CSTU 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 KSC3953CSTU?
For technical support, including KSC3953CSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC3953CSTU requirements.
6.How does Aetrix verify that KSC3953CSTU is sourced from the original manufacturer or authorized distributors?
All KSC3953CSTU 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 KSC3953CSTU meets industry standards.
7.What is the process for return or replacement of KSC3953CSTU?
All KSC3953CSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC3953CSTU, 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 KSC3953CSTU part is unused and in its original packaging.
Return procedure for KSC3953CSTU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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