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AD724:  RGB to NTSC/PAL Encoder

Product Details


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.

FEATURES and BENEFITS

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

Functional Block Diagram for AD724

Documentation

Title Content Type File Type
AD724: RGB to NTSC/PAL Encoder Data Sheet  (Rev B, 08/1999) (pdf, 205 kB) Data Sheets PDF
AN-336: JPEG Compression Application Notes HTML
AN-205: Video Formats and Required Load Terminations  (pdf, 241 kB) Application Notes PDF
Advantiv™ Advanced Television Solutions  (pdf, 549 kB)
Enhancing the HD system design and consumer experience, Analog Devices offers its Advantiv portfolio of video and audio integrated circuit solutions, specifically developed and optimized for advanced television applications.
Overview PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

SampleSample & Buy

Price, packaging, availability

AD724 Model Options
Model Package Pins Temp.
Range
Packing,
Qty
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD724JR Status: Production 16 ld SOIC - Wide 16 Comm. Tube, 47 $7.86 $7.11 N  Material Info PCN Purchase Sample
AD724JR-REEL Status: Production 16 ld SOIC - Wide 16 Comm. Reel, 1000 $7.86 $7.11 N  Material Info PCN Purchase
AD724JR-REEL7 Status: Last Time Buy 16 ld SOIC - Wide 16 Comm. Reel, 400 $7.86 $7.11 N  Material Info PCN/PDN Purchase
AD724JRZ Status: Production 16 ld SOIC - Wide 16 Comm. Tube, 47 $6.81 $6.15 Y  Material Info PCN Purchase Sample
AD724JRZ-R7 Status: Production 16 ld SOIC - Wide 16 Comm. Reel, 400 $6.81 $6.15 Y  Material Info PCN Purchase
AD724JRZ-RL Status: Production 16 ld SOIC - Wide 16 Comm. Reel, 1000 $6.81 $6.15 Y  Material Info PCN Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

AD724 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD724-EBZ Status: Production Evaluation Board $266.00 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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