Analog Devices AD720
The AD720 and AD721 provide a complete, fully calibrated function, requiring only termination resistors, bypass capacitors, a clock input at four times the subcarrier frequency, and a composite sync pulse. The chip operates from ± 5 V supplies.FEATURES
Composite Video Output Chrominance and Luminance (S-Video) Outputs No External Filters or Delay Lines Required Drives 75 Ω Reverse-Terminated Loads Compact 28-Pin PLCC Logic Selectable NTSC or PAL Encoding Modes Automatically Selects Proper Chrominance Filter Cutoff Frequency for Encoding Standard Logic Selectable Encode or Power-Down Mode (AD720 Only) Logic Selectable Encode or Bypass Mode (AD721 Only) Low Power: 200 mW typicalAPPLICATIONS
RGB to NTSC or PAL Encoding Drive RGB Signals into 75 Ω Load (AD721 Only) PRODUCTDESCRIPTION
RGB to NTSC/PAL Encoders AD720/AD721 (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide a composite video output. All three outputs are available separately at voltages of twice the standard signal levels as required for driving 75 Ω reverse terminated cables. The AD721 also features a bypass mode, in which the RGB inputs may bypass the encoder section of the IC via three gain-of-two amplifiers suitable for driving 75 Ω reverse terminated cables.