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onsemi KSC3953CS
- Part No.:
- KSC3953CS
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
KSC3953CS.pdf
- Description:
- TRANS NPN 120V 0.2A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,534
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Product details
Overview
KSC3953CS 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.), and Cre = 1.7 pF (typ.). It operates with low saturation voltages (VCE(sat) = 1.0 V at IC = 30 mA/IB = 3 mA) and supports high-voltage switching in analog video driver circuits.
For engineers reviewing the KSC3953CS datasheet, pinout, applications, or equivalent options, key selection criteria include its 120 V breakdown rating, 400 MHz gain-bandwidth product, TO-126 package thermal performance (PC = 8 W at TC = 25°C), and verified use in CRT video output amplification.
Technical Context
This NPN bipolar junction transistor delivers high-voltage capability (BVCBO = 120 V, BVEBO = 3 V) and high-speed response (fT = 400 MHz at VCE = 10 V, IC = 50 mA), enabling stable operation in wideband video signal amplification. Its low reverse transfer capacitance (Cre = 1.7 pF at VCB = 30 V, f = 1 MHz) minimizes feedback instability in high-gain configurations.
The device exhibits DC current gain ranging from hFE = 40–80 (Class C) or 60–120 (Class D) at VCE = 10 V, with tight saturation characteristics: VCE(sat) ≤ 1.0 V and VBE(sat) ≤ 1.0 V under IC = 30 mA/IB = 3 mA drive - critical for efficient switching in linear video output stages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 120 V - enables safe operation in CRT anode drive and high-voltage video amplifier rails |
| fT | 400 MHz (typ.) - supports bandwidth-critical CRT video signal amplification up to ~100 MHz fundamental |
| Cre | 1.7 pF (typ.) - reduces Miller effect and improves high-frequency stability in common-emitter video stages |
| IC (DC) | 200 mA - sufficient for driving deflection yoke compensation and video output loads |
| PC (TC=25°C) | 8 W - allows high-power dissipation when mounted on heatsink, supporting continuous video output duty |
| hFE (Class C) | 40–80 - provides predictable DC biasing for linear video output stage design |
| VCE(sat) | ≤1.0 V at IC = 30 mA/IB = 3 mA - ensures low conduction loss and minimal voltage headroom requirement |
Pinout & Package
Package: TO-126 - thermally robust through-hole package with collector tab (Pin 2) electrically connected to case for direct heatsinking; rated for 8 W dissipation at TC = 25°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Current sink terminal; referenced to ground or cathode return path in CRT video output |
| 2 | Collector | Main power output terminal; electrically tied to metal tab for thermal and electrical grounding to heatsink |
| 3 | Base | Control input; accepts low-current drive (e.g., 3 mA) to switch or linearly modulate 30–100 mA collector current |
Key Features
| Feature | Design Value |
|---|---|
| High fT bandwidth | 400 MHz typical - preserves video signal rise/fall integrity in CRT RGB or sync amplifiers |
| High VCEO rating | 120 V - accommodates CRT flyback-induced voltage spikes and HV supply rails |
| Low Cre capacitance | 1.7 pF typical - suppresses high-frequency oscillation in wideband video gain stages |
| TO-126 thermal design | 8 W PC at TC = 25°C - enables reliable operation without forced air, using simple aluminum heatsink |
| Controlled hFE spread | Class C (40–80) or Class D (60–120) - simplifies bias network design across production lots |
Applications
| CRT Video Output Amplifier | Deflection Yoke Compensation |
|---|---|
Use Scenario: Amplifying RGB or composite video signals prior to CRT cathode drive with minimal distortion and overshoot. IC Role / Device Role / Timing Role: Linear NPN transistor operating in Class-A or AB mode to deliver high-slew-rate current into capacitive CRT grid load. Use Value: 400 MHz fT and low Cre ensure flat frequency response to 30–50 MHz, preserving video edge fidelity. | Use Scenario: Compensating phase lag in horizontal/vertical deflection yoke current loops to stabilize scan linearity. IC Role / Device Role / Timing Role: High-voltage, medium-current switch providing precise timing-controlled correction pulses synchronized to scan retrace. Use Value: 120 V VCEO withstands flyback transients; 200 mA DC rating sustains continuous yoke compensation current. |
| High-Voltage Signal Buffer | Analog Sync Separator Stage |
Use Scenario: Isolating and buffering high-amplitude sync or blanking pulses between video processing ICs and CRT control inputs. IC Role / Device Role / Timing Role: Emitter-follower configured NPN buffer delivering low-impedance drive while maintaining DC level shift tolerance. Use Value: Low VCE(sat) (≤1.0 V) and high hFE minimize insertion loss and preserve pulse amplitude integrity. | Use Scenario: Extracting and conditioning composite sync signals from baseband video for timing recovery in CRT controller ICs. IC Role / Device Role / Timing Role: Fast-switching NPN comparator or limiter stage rejecting noise while preserving sync edge timing. Use Value: 400 MHz fT enables clean edge detection of sub-µs sync transitions; low Cre prevents false triggering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN high-voltage, high-speed transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD127G | VCEO = 100 V (lower), fT = 3 MHz (much lower), TO-220 package | Not suitable for video bandwidth; limited to <1 MHz switching or linear audio | Select only if high-voltage but low-frequency operation suffices and TO-220 mounting is preferred |
| 2SC4544 | VCEO = 120 V (same), fT = 250 MHz (lower), Cre = 2.5 pF (higher), TO-126 | Acceptable for CRT video where bandwidth margin >100 MHz is not required | Use when cost sensitivity outweighs need for full 400 MHz bandwidth and lowest Cre |
Compared with MJD127G and 2SC4544, the KSC3953CS uniquely combines 120 V rating, 400 MHz fT, and 1.7 pF Cre in TO-126 - making it the only option among the three qualified for demanding CRT video output amplification requiring both speed and voltage headroom.
Availability
KSC3953CS is available at Aetrix Electronics and suitable for CRT display systems, analog video signal conditioning, and high-voltage pulse amplification requiring stable component supply and long-lifecycle support.
Supply support for KSC3953CS 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 components before its acquisition by ON Semiconductor in 2016.
The KSC3953CS belongs to Fairchild's legacy high-voltage, high-speed NPN transistor family engineered specifically for analog video output and CRT deflection circuitry in consumer and industrial display equipment.
FAQ
What is the maximum collector-emitter voltage rating for KSC3953CS?
The KSC3953CS has a guaranteed minimum collector-emitter breakdown voltage (BVEBO) of 120 V at IC = 1 mA with RBE = ∞. This rating allows safe operation in CRT video output stages exposed to flyback-induced transients and high DC supply rails. The KSC3953CS must not be operated beyond this limit to avoid avalanche failure or parametric shift.
Does KSC3953CS have a specified current gain range, and how is it classified?
Yes, the KSC3953CS is classified into hFE groups: Class C specifies hFE = 40–80 and Class D specifies hFE = 60–120, both measured at VCE = 10 V and IC = 10 mA. The suffix "CS" denotes Class C specification. This binning enables predictable bias design in linear video amplifier applications where gain stability directly impacts output linearity.
What package type does KSC3953CS use, and how is the collector terminal connected?
The KSC3953CS uses the TO-126 package, with Pin 2 designated as the collector and electrically connected to the metal tab. This construction allows direct mechanical and thermal attachment to a heatsink, supporting its 8 W power dissipation rating at TC = 25°C. The emitter (Pin 1) and base (Pin 3) are insulated leads.
Is KSC3953CS suitable for RF amplifier applications above 100 MHz?
The KSC3953CS achieves fT = 400 MHz (typ.) at VCE = 10 V and IC = 50 mA, indicating usable gain up to ~100–150 MHz depending on bias and layout. However, it is not characterized or optimized for narrowband RF power amplification; its primary validation is in wideband analog video signal paths. For dedicated RF use, consult S-parameter data - not provided in the KSC3953CS datasheet.
How does the reverse transfer capacitance (Cre) of KSC3953CS affect video amplifier stability?
The KSC3953CS has Cre = 1.7 pF (typ.) at VCB = 30 V and f = 1 MHz - a low value that directly reduces Miller multiplication in common-emitter video amplifiers. This minimizes unwanted feedback and potential oscillation, especially critical in high-gain CRT video output stages where stability margins are tight and load capacitance is significant.
KSC3953CS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Bulk
- 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
KSC3953CS FAQ
1.How can I place an order for KSC3953CS through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC3953CS 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 KSC3953CS reliable?
The price and inventory of KSC3953CS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC3953CS is usually 5 days.
3.What payment methods are accepted for KSC3953CS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC3953CS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC3953CS?
KSC3953CS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC3953CS 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 KSC3953CS?
For technical support, including KSC3953CS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC3953CS requirements.
6.How does Aetrix verify that KSC3953CS is sourced from the original manufacturer or authorized distributors?
All KSC3953CS 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 KSC3953CS meets industry standards.
7.What is the process for return or replacement of KSC3953CS?
All KSC3953CS units undergo pre-shipment inspection (PSI). If there is an issue with KSC3953CS, 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 KSC3953CS part is unused and in its original packaging.
Return procedure for KSC3953CS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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