AD723是一款低成本RGB转NTSC/PAL
encoder,可将模拟红色、绿色和蓝色分量信号转换为相应的亮度和色度信号,以在NTSC或PAL电视上显示。亮度(Y)和色度(C)信号可分别独立用于S-视频,或者合并用于复合视频(CV)。所有输出均可独立提供,并针对驱动75 Ω负载进行了优化。为降低功耗,该器件使用有源端阻抗。
The intelligent load detection feature shuts down unused outputs and can be used to monitor the presence or absence of an external TV signal for plug-and-play operation. In addition, when the RGB monitor is disconnected, the logic-controlled three-way switch on the input solves the problem of providing applications with different load conditions. When the RGB monitor is not present, the user can enable the R, G, and B-terminal impedances. When the RGB monitor is working, this solution ensures that there is no loss of video bandwidth.
In PC applications, graphics controllers offer flicker filter support and direct access to memory. Underscan compensation required for non-video or DVD applications can be supported by selecting the appropriate RGB output clock and sync interval.
An optional luminance trap (YTRAP) can be used to reduce the cross-color artifacts caused by the subcarrier frequency information in the Y signal.
The AD723 is available in a 28-pin TSSOP package and can be operated from a 2.7 V to 5.5 V supply.