AD724JR-REEL:  RGB to NTSC/PAL Encoder

The AD724 is a low cost RGB to NTSC/PAL Encoder that converts red, green and blue color component signals into their corresponding luminance (baseband amplitude) and chrominance (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide composite video output. All three outputs can simultaneously drive 75 (ohm), reverse-terminated cables. All logical inputs are CMOS compatible. The chip operates from a single +5 V supply. No external delay lines or filters are required. The AD724 may be powered down when not in use.

The AD724 accepts either FSC or 4FSC clock. When a clock is not available, a low cost parallel-resonant crystal (3.58 MHz (NTSC) or 4.43 MHz (PAL)) and the AD724’s on-chip oscilla-tor generate the necessary subcarrier clock. The AD724 also accepts the subcarrier clock from an external video source.

The interface to graphics controllers is simple: an on-chip logic “XNOR” accepts the available vertical (VSYNC) and horizontal sync (HSYNC) signals and creates the composite sync (CSYNC) signal on-chip. If available, the AD724 will also accept a standard CSYNC signal by connecting VSYNC to +5 V and applying CSYNC to the HSYNC pin. The AD724 contains decoding logic to identify valid horizontal sync pulses for correct burst insertion.

Delays in the U and V chroma filters are matched by an on-chip sampled-data delay line in the Y signal path. To prevent aliasing, a prefilter at 5 MHz is included ahead of the delay line and a post-filter at 5 MHz is added after the delay line to suppress harmonics in the output. These low-pass filters are optimized for minimum pulse overshoot. The overall luma delay, relative to chroma, has been designed to be time aligned for direct input to a television’s baseband. The AD724 comes in a space-saving SOIC and is specified for the 0°C to +70°C commercial temperature range.

An evaluation board is available for this product and may be ordered using the following product number: AD724-EB

AD724JR-REEL 特点
AD724JR-REEL 功能框图

AD724 芯片订购指南
产品型号 产品状态 封装 引脚 温度范围
AD724-EBZ 量产 评估板 - 商业
AD724JR 量产 16 ld SOIC - Wide 16 商业
AD724JR-REEL 量产 16 ld SOIC - Wide 16 商业
AD724JR-REEL7 量产 16 ld SOIC - Wide 16 商业
AD724JRZ 量产 16 ld SOIC - Wide 16 商业
AD724JRZ-R7 量产 16 ld SOIC - Wide 16 商业
AD724JRZ-RL 量产 16 ld SOIC - Wide 16 商业
AD724JR-REEL 应用技术支持与电子电路设计开发资源下载
  1. AD724 数据手册DataSheet下载 . pdf
  2. Analog Devices, Inc.ADI 美国模拟器件公司产品订购手册 .pdf