LM2418T - Triple 30 MHz CRT Driver | National Semiconductor
MPN： LM2418T ✓ 啟用中LM2418T 概覽
A CRT driver is a specialized video amplifier within the interface IC and video IC hierarchy. It sits between a graphics signal source and the electron-gun cathode circuitry of a CRT display. Unlike a general-purpose low-voltage signal amplifier, a CRT driver must combine wide video bandwidth, large output swing, low distortion, and the ability to operate from an elevated supply voltage. The LM2418T implements three such output channels in one integrated package for multi-channel color video systems.
The principal documented characteristics are triple-channel operation, 30 MHz bandwidth, greater-than-50 V peak-to-peak output swing, and operation from a 90 V supply. Each section provides its own nominal voltage gain and cathode-drive output. These characteristics allow one component to replace three separate discrete video-output stages when the display design requires red, green, and blue cathode drive. Its integrated three-channel architecture also reduces the number of active driver packages and simplifies channel matching at the system level.
Technically, the LM2418 is a large-signal video amplifier rather than a high-speed digital logic device or a low-voltage op amp. Its operating point depends on the elevated B+ supply used in CRT displays. The output swing is therefore tied to the supply voltage, while the 30 MHz bandwidth establishes the usable video-frequency range. Designers must observe the manufacturer’s supply, output, pin, and thermal limits and should not substitute a conventional TO-220-11 power regulator or transistor package without verifying every connection and operating condition.
Typical uses include legacy VGA monitor cathode-drive circuits, CRT graphics adapters, CRT-based video test equipment, and repair or modernization projects that retain a 90 V-class display rail. In each case, the LM2418T supplies three amplified video outputs to the display’s cathode network. Its primary advantage is integration: one three-channel device replaces separate red, green, and blue amplifier stages while preserving a 30 MHz bandwidth class.
The critical design consideration is the CRT supply and return-current environment. Keep high-voltage and video-return routing compact, maintain the required isolation and clearance margins specified for the display design, and use the manufacturer pin descriptions when assigning PCB connections. Because the package contains exposed supply and ground structures, thermal performance depends on adequate copper area and correct mounting hardware. Confirm the final cathode-drive waveform, output loading, and heat dissipation in the intended display before production.
This page consolidates the documented LM2418T identity, operating limits, package information, application context, and engineering considerations into one design-oriented reference. It also distinguishes verified drop-in alternatives from unverified substitutions, helping engineers preserve the TO-220-11 footprint, three-channel architecture, 30 MHz bandwidth, and elevated-supply CRT-drive requirements during legacy design maintenance.
直接替換替代品，適用於 LM2418T — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此產品無可直接替換的替代品。
申請替代品LM2418T 規格
| Device Type | Triple large-signal CRT cathode video amplifier |
| Number of Output Channels | 3 channels |
| Video Bandwidth | 30 MHz per channel |
| Maximum Output Swing | Greater than 50 V peak-to-peak at 90 V supply |
| Power Supply Used for Stated Output Swing | 90 V |
| Output Drive Configuration | 3 independent large-signal cathode outputs |
| Intended Display Type | VGA color graphics display |
| Package Type | TO-220-11 through-hole package |
| Package Pin Count | 11 pins |
| 安裝類型 | Through-hole |
LM2418T 11 pins 腳位配置指南
LM2418T（11 pins 封裝）的腳位配置。 腳位編號、功能與連接圖定義於製造商資料手冊中。請參閱該手冊以取得確切的封裝尺寸與焊接指引。
無詳細腳位定義資料： LM2418T.
請參閱 資料表 以查看完整腳位配置。
典型應用
LM2418T 適用於 6 應用s: VGA CRT Monitor Cathode Drive, Legacy CRT Graphics Adapter, CRT Video Test Equipment, CRT Display Repair and Maintenance, Analog Color Video Demonstration Board, Specialty Analog Video Amplifier.
VGA CRT Monitor Cathode Drive
The LM2418T fits a VGA color monitor because it provides three large-signal video amplifiers for the red, green, and blue cathode channels. According to the National Semiconductor manufacturer datasheet, each channel supports 30 MHz operation, and output swings greater than 50 V peak-to-peak are obtained with a 90 V supply. The device therefore consolidates three high-voltage video-output stages into one TO-220-11 package. The designer must still verify cathode loading, monitor isolation requirements, thermal dissipation, and the complete pin connections before using the amplifier in production hardware.
Legacy CRT Graphics Adapter
A legacy graphics adapter can use the LM2418T as the final analog video stage feeding CRT cathodes. Its three-channel organization matches a color display architecture, while the documented 30 MHz bandwidth provides margin for VGA-class video signals. The 90 V operating example and greater-than-50 V peak-to-peak swing distinguish this device from ordinary low-voltage op amps. For a new adapter design, include suitable high-voltage routing, adequate grounding, thermal provisions for the TO-220-11 package, and protection consistent with the target display’s cathode network.
CRT Video Test Equipment
The LM2418T can form the cathode-drive output section of a CRT test or demonstration system because it supplies three amplified video channels with 30 MHz bandwidth. The manufacturer datasheet identifies greater-than-50 V peak-to-peak output swing at a 90 V supply, allowing a compact three-output amplifier arrangement for bench equipment. Its value is most pronounced when reproducing legacy VGA display behavior. Test-equipment designers should account for the elevated supply, measurable output loading, waveform distortion, thermal conditions, and appropriate high-voltage clearance rather than treating the device as a general-purpose low-voltage amplifier.
CRT Display Repair and Maintenance
The LM2418T is suited to repair and maintenance of compatible legacy CRT monitors because it directly replaces the function of three large-signal cathode amplifiers. Its documented 30 MHz bandwidth and greater-than-50 V peak-to-peak output capability at 90 V provide the core operating characteristics expected in a color VGA display. During repair, confirm that the original circuit used the same LM2418T pinout and electrical topology rather than assuming any TO-220-11 video amplifier is interchangeable. Inspect the flyback-derived supply, cathode load, grounding, solder joints, and thermal mounting rather than relying on transistor-level substitution.
Analog Color Video Demonstration Board
A laboratory board that recreates analog color-video drive behavior can use the LM2418T to generate three cathode-output signals from separate video channels. The 30 MHz bandwidth supports the intended VGA-style video range, and the documented greater-than-50 V peak-to-peak swing at 90 V provides the required drive amplitude. Because the outputs operate at elevated voltage, the board requires careful isolation, short return paths, controlled test points, and safeguards for bench use. Component selection should focus on the documented cathode-drive function rather than generic amplifier bandwidth alone.
Specialty Analog Video Amplifier
The LM2418T can serve in specialized analog video systems requiring three synchronized, large-signal output channels. Its 30 MHz bandwidth makes it more appropriate for high-definition analog video-era signals than for slow sensor conditioning, while the 90 V supply example and greater-than-50 V peak-to-peak swing support CRT cathode levels. The TO-220-11 package favors through-hole serviceable assemblies and effective heat sinking. Any use outside a conventional VGA monitor should be validated against output loading, distortion, stability, thermal rise, and the manufacturer’s electrical limits.
工程參考資料，適用於 LM2418T — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 |
|---|---|
| Manufacturer | National Semiconductor |
| Package | TO-220-11 |
| Device Type | Triple large-signal CRT video amplifier |
| Number of Video Channels | 3 |
| Video Bandwidth | 30 MHz |
| Documented Output Swing | Greater than 50 V peak-to-peak at 90 V supply |
| Intended Application | VGA color graphics display CRT cathode drive |
| Mounting Type | Through-hole |
主要差異化特點
- Three integrated cathode-drive channels (對比LM2418T)
- 30 MHz video bandwidth (對比LM2418T)
- Large CRT-drive output swing (對比LM2418T)
設計說明
Treat the LM2418T as an elevated-voltage video-output device rather than a conventional low-voltage op amp. Route its cathode outputs with controlled geometry, keep the return-current path short, and maintain clearances appropriate to the 90 V operating example in the target CRT display. Use the manufacturer pin-description table for every connection. Do not infer ground, output, or input assignments from the TO-220-11 outline because an incorrect connection can damage a high-voltage display.
The LM2418T’s three large-signal amplifiers dissipate power in an 11-pin TO-220-11 package with an elevated operating supply. Mount the device with the manufacturer-recommended hardware and provide adequate copper area and airflow for the expected load. Check the ambient temperature, channel loading, and worst-case supply condition against the datasheet’s power-dissipation and temperature limits. Any heat-sink solution should be verified after installation because package mounting pressure and thermal interface conditions affect junction temperature.
A generic TO-220-11 device is not a safe substitute for the LM2418T. Verify the 11-pin footprint, all pin functions, three-channel topology, 30 MHz bandwidth, output-swing capability, and operating-supply requirements. Also confirm the cathode load and signal source impedance. In a repair, inspect the original schematic and board artwork rather than relying on physical appearance; in a new design, validate startup, output saturation, thermal behavior, and stability before connecting the CRT.
Preserve the integrity of all three video paths from the source through the LM2418T to the CRT cathode network. Keep the high-bandwidth output routes compact, minimize unnecessary loop area, and maintain consistent grounding between the video source and the display return. Because the device provides 30 MHz channels and a greater-than-50 V peak-to-peak swing at 90 V, observe probe, termination, and isolation requirements when measuring waveforms to avoid inaccurate readings or damage to the display and test equipment.
合規資訊
No explicit RoHS, REACH, lead-free, halogen-free, or conflict-minerals status is stated in the LM2418T product documentation indexed for this part. AEC-Q100 is not applicable to this legacy CRT-driver product.
