AD721JP RGB to NTSC/PAL Encoder | Analog Devices
MPN： AD721JP ✗ 停產AD721JP 概覽
An RGB-to-NTSC/PAL encoder is a video-signal conversion IC that accepts red, green, and blue analog color components and combines them into a standard composite television signal. Within the broader signal-processing hierarchy, the AD721JP belongs to the color-signal encoder class, which supports display, broadcast, video-production, image-capture, and industrial monitoring systems. Separate S-Video outputs retain chrominance and luminance as independent signals, while the composite output combines the three RGB input channels for conventional video connections.
Key features include logic-selectable NTSC and PAL encoding modes, a composite video output, individual chrominance and luminance outputs, and no requirement for external filters or delay lines. Its ability to drive 75-ohm reverse-terminated loads simplifies analog video output design because downstream cable and video-circuit impedances are matched at the device interface. The 28-pin PLCC package also supports compact, socket-compatible legacy video equipment layouts.
Internally, the encoder translates the red, green, and blue input signals into the amplitude and timing relationships required by composite video. Logic selection determines whether the generated chrominance information follows NTSC or PAL conventions, reducing the need for separate encoder ICs when a system must support both standards. The ±5 V analog supply arrangement provides compatible operating rails for the RGB input, modulation, and output stages commonly used in professional analog video electronics.
Typical applications include professional video switchers, frame synchronizers, broadcast and production equipment, industrial video monitors, test and measurement instruments, RGB-to-video interface boards, and legacy computer-video adapters. Because the IC produces composite and S-Video simultaneously, it can feed separate baseband video sections without requiring duplicated encoding circuitry.
A key design consideration is signal termination. The composite and S-Video outputs are intended for 75-ohm reverse-terminated loads, so downstream cable routing and impedance matching directly affect picture quality. Place supply bypass capacitors near the device, route RGB inputs away from output nodes, and preserve the logic levels required for NTSC/PAL mode selection. Verify the complete color-adjustment and synchronization implementation against the Analog Devices AD721/AD721 datasheet.
This product summary consolidates the encoder functions, package details, output capabilities, application guidance, and replacement considerations into a design-focused reference. It also identifies where a same-footprint candidate requires review rather than presenting every related device as an automatic substitute.
直接替換替代品，適用於 AD721JP — 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。
AD721JRZ
✅ 直接替換📋 參考替代品（不在目錄中）
AD721JP 最大額定值與電氣特性
| Product Type | RGB to NTSC/PAL color-signal encoder |
| Manufacturer | Analog Devices |
| 供應電壓 | ±5 V |
| Typical Supply Condition for Specifications | ±5 V at TA = +25 °C |
| Number of Package Pins | 28 pins |
| 封裝 | 28-pin plastic leaded chip carrier (PLCC-28) |
| 安裝類型 | Surface mount |
| Video Output Type | Composite video output |
| S-Video Outputs | Separate chrominance and luminance outputs |
| Encoding Modes | Logic-selectable NTSC or PAL |
| Output Load Capability | 75-ohm reverse-terminated loads |
| External Filters or Delay Lines | Not required |
| RGB Signal Inputs | RDIN, GRIN, and BLIN |
| RoHS 狀態 | unknown |
AD721JP 28-pin plastic leaded chip carrier (plcc-28) 腳位配置指南
AD721JP（28-pin plastic leaded chip carrier (plcc-28) 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： AD721JP.
請參閱 資料表 以查看完整腳位配置。
典型應用
AD721JP 適用於 6 應用s: Broadcast Video Switching, S-Video Production Equipment, Industrial Video Monitoring, Video Test and Measurement, Legacy Computer Video Adapters, RGB Video Interface Cards.
Broadcast Video Switching
The AD721JP fits professional analog-video switching systems that must convert RGB sources into composite video while also providing separate chrominance and luminance signals for S-Video routing. Its logic-selectable NTSC and PAL modes allow one encoder position to accommodate different television standards, while the 28-pin PLCC package supports established broadcast-equipment layouts. The integrated approach eliminates external filters and delay lines, reducing circuit complexity. During layout, keep RGB inputs away from composite and S-Video outputs, use low-impedance supply connections, and implement the manufacturer-specified 75-ohm reverse-termination networks.
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S-Video Production Equipment
The AD721JP is suitable for video-production equipment requiring simultaneous composite and S-Video generation from an RGB source. Separate chrominance and luminance outputs allow S-Video processing or routing without splitting the composite signal externally, while logic-selected NTSC or PAL encoding supports equipment intended for multiple standards. Its ±5 V supply arrangement and integrated encoding reduce external analog delay stages. Engineers should preserve the specified 75-ohm reverse termination and verify synchronization timing, sync polarity, and signal amplitude against the target video standard before production use.
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Industrial Video Monitoring
The AD721JP can serve as the baseband color encoder in an industrial monitoring system that accepts RGB signals and distributes composite video to monitors, recorders, or inspection equipment. Logic-selectable NTSC and PAL modes are useful where equipment may operate across regional television standards, and the availability of separate S-Video outputs can provide a cleaner path to compatible displays. Because the encoder integrates functions normally requiring external filters or delay lines, the analog layout should focus on controlled impedance, grounding, bypass capacitance, and stable reference-video connections rather than additional timing-network design.
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Video Test and Measurement
The AD721JP is appropriate for analog video test equipment that needs to generate composite and S-Video outputs from RGB test sources. The composite output supports conventional waveform observation, while separate chrominance and luminance outputs simplify analysis of color and synchronization behavior. NTSC or PAL can be selected through logic control, allowing the same instrument architecture to address multiple test standards. For bench and instrument designs, use short video paths, maintain the specified 75-ohm reverse termination, and decouple the ±5 V rails near the device to prevent supply disturbances from appearing as video artifacts.
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Legacy Computer Video Adapters
The AD721JP is applicable to legacy computer-video adapters that convert RGB graphics into composite television output. Its integrated composite and S-Video outputs provide practical connector options for displays, projectors, and capture equipment, while selectable NTSC and PAL modes support systems intended for different regions. The 28-pin plastic leaded chip carrier package is especially relevant when repairing or replicating established PLCC-based boards. Preserve the original pin assignments, synchronization path, resistor networks, and output termination because changing those surrounding values can affect color gain and timing even when the encoder itself is unchanged.
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RGB Video Interface Cards
The AD721JP fits modular RGB video interface cards that convert computer or industrial graphics signals into composite and S-Video outputs. Logic-controlled NTSC and PAL selection permits a shared card design to serve several markets, and the absence of required external filters or delay lines helps simplify the analog section. The device's integrated encoder functions are useful when the card must provide multiple analog outputs from one RGB source. For reliable implementation, verify the accepted input amplitudes and resistances from the AD721/AD721 datasheet, maintain short high-impedance routing for RGB inputs, and terminate each output for its intended 75-ohm load.
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推薦產品摘要
工程參考資料，適用於 AD721JP — 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 | AD721JRZ |
|---|---|---|
| Brand | Analog Devices | Analog Devices |
| Package | PLCC-28 | PLCC-28 |
| Product Type | RGB to NTSC/PAL encoder | Related AD721-family encoder |
主要差異化特點
- Integrated composite and S-Video generation (對比AD721JRZ)
- Single-device NTSC and PAL selection (對比AD721JRZ)
- Simplified analog output stage (對比AD721JRZ)
設計說明
Route RDIN, GRIN, and BLIN as short, matched paths on the PCB and keep them physically separated from the composite, chrominance, and luminance outputs. The AD721JP combines sensitive color inputs with high-level video outputs, so unintended coupling between these paths can create color shifts, ringing, or unstable sync behavior. Use a continuous ground reference beneath the analog section, avoid vias in sensitive input routes, and confirm the output routing matches the manufacturer reference circuit.
Implement the specified 75-ohm reverse termination for each connected video output and do not add termination indiscriminately to outputs that are already terminated elsewhere in the chain. Incorrect impedance can alter amplitude, bandwidth, and reflection behavior. Also use the logic truth table to select NTSC or PAL rather than assuming that a high or low level automatically corresponds to either standard.
Place bypass capacitors close to the ±5 V supply pins and provide low-impedance connections between each supply pin and the ground reference. Estimated: using a supply-decoupling arrangement of 0.1 µF plus 1 to 10 µF near the device can reduce high-frequency supply impedance, but the final capacitor values should follow the manufacturer reference design and the measured impedance of the board and cable environment.
Do not substitute AD721JRZ solely because it appears in the same product family. Before redesigning a populated board, compare the exact pinout, package orientation, temperature range, supply tolerances, RGB input scaling, output levels, synchronization requirements, and lifecycle status between the two suffixes. Marking differences alone do not establish electrical or pin-for-pin interchangeability.
合規資訊
The AD721JP is a legacy analog video encoder; no specific RoHS, REACH, lead-free, halogen-free, or conflict-minerals declaration is identified in the referenced material. AEC-Q100 qualification is not applicable to this device class.
