AD722

Features:

Low Cost, Integrated Solution
+5 V Operation
Accepts FSC Clock or Crystal, or 4FSC Clock
Composite Video and Separate Y/C (S-Video) Outputs
Minimal External Components:
      No External Filters or Delay Lines Required
      Onboard DC Restoration
      Accepts Either HSYNC & VSYNC or CSYNC
Phase Lock to External Subcarrier
Drives 75 Ω Reverse-Terminated Loads
Logic Selectable NTSC or PAL Encoding Modes
Compact 16-Pin SOIC


Application

RGB to NTSC or PAL Encoding


Pinout




Specifications

Supply Voltage VS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6 V
Internal Power Dissipation  . . . . . . . . . . . . . . . . . . . . .600 mW
Operating Temperature Range . . . . . . . . . . . . . .0°C to +70°C
Storage Temperature Range  . . . . . . . . . . . .65°C to +125°C
Lead Temperature Range (Soldering 60 sec)  . . . . . . . +300°C


Description

The AD722 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 Ω, 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 AD722 may be powered down when not in use.

The AD722 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 AD722's on-chip oscillator generate the necessary subcarrier clock. The AD722 also accepts the subcarrier clock from an external video source.The interface to VGA Controllers and MPEG Video Decoders 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 AD722 will also accept a standard CSYNC signal by connecting VSYNC to +5 V and applying CSYNC to HSYNC pin. The AD722 contains decoding logic to identify valid HSYNC pulses for correct burst insertion.