AD722 Analog Devices, AD722 Datasheet
AD722
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AD722 Summary of contents
Page 1
... No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 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 oscilla- tor generate the necessary subcarrier clock ...
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... AD722–SPECIFICATIONS Parameter SIGNAL INPUTS (RDIN, GRIN, BLIN) Input Amplitude Black Level 1 Input Resistance Input Capacitance LOGIC INPUTS (SYNC, FSC, ENCD, NTSC) Logic LO Input Voltage Logic HI Input Voltage Logic LO Input Current (DC) Logic HI Input Current (DC) 2 VIDEO OUTPUTS Luminance (LUMA) Roll-off @ 5 MHz ...
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... ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD722 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality ...
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... AD722 Pin Mnemonic 1 STND 2 AGND 3 FIN 4 APOS 5 ENCD 6 RIN 7 GIN 8 BIN 9 CRMA 10 COMP 11 LUMA 12 SELECT 13 DGND 14 DPOS 15 VSYNC 16 HSYNC *The Luminance, Chrominance, and Composite Outputs are at twice normal levels for driving 75 DPOS Circuit A APOS 3 PIN DESCRIPTIONS Description A Logical HIGH input selects NTSC encoding. ...
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... SLOW CLAMP TO 0.00V @ 6.72µs 0.5 0.0 PRECISION MODE OFF SOUND-IN-SYNC OFF SYNCHRONOUS SYNC = SOURCE FRAMES SELECTED : –0 µs Figure 3. Modulated Pulse and Bar, PAL REV. 0 Typical Characteristics–AD722 0.10 COMPOSITE SONY VIDEO MONITOR MODEL 1342 0.5 75 0.0 TEKTRONIX VM700A WAVEFORM MONITOR –0.5 0 ...
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... AD722–Typical Characteristics Figure 7. 100% Color Bars on Vector Scope, PAL 0.10 APL = 11.6% 525 LINE NTSC NO FILTERING SLOW CLAMP TO 0.00V @ 6.63µs 0.5 0.0 PRECISION MODE OFF SYNCHRONOUS SYNC = SOURCE FRAMES SELECTED : 1 2 –0 µs Figure 8. Multipulse, NTSC 0.10 APL = 11.4% 625 LINE PAL NO FILTERING SLOW CLAMP TO 0.00V @ 6.72µs ...
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... BLUE DC CLAMP THEORY OF OPERATION The AD722 was designed to have three allowable modes of ap- plying a clock via the FIN pin. These are FSC (frequency of subcarrier, 3.579545 MHz for NTSC or 4.433618 MHz for PAL) mode with CMOS clock applied, FSC mode using on- chip crystal oscillator, and 4FSC mode with CMOS clock ap- plied ...
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... The CSYNC signal (after the XNOR gate) also goes to the digi- tal section of the AD722 where it is clocked 2FSC clock. The digital section then measures the width of the CSYNC pulses to separate horizontal pulses from vertical equalizing and serration pulses ...
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... VGA OUTPUT CONNECTOR Figure 15. Interfacing the AD722 to the (Interlaced) VGA Port REV. 0 resistor is required close to each AD722 output, while 75 ground should terminate the far end of each line. The outputs have a dc bias and must be ac coupled for proper operation ...
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... For a synchronous NTSC system, the internal 4FSC (14.31818 MHz) clock that drives the VGA controller can be used for FIN on the AD722. This signal is not directly accessible from outside the computer, but it does appear on the VGA card separate RGB monitor is also to be used not possible to simply connect it to the R, G, and B signals ...
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... This correction to TV broadcasts was made in the early days of TV and is the standard to this day. The delay line used in the luminance path of the AD722 creates a –170 ns chrominance delay. This will be realigned by the RF section when it is used for receiving the signal. ...
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... AD722 Synchronous vs. Asynchronous Operation The source of RGB video and synchronization used as an input to the AD722 in some systems is derived from the same clock signal as used for the AD722 subcarrier input (FIN). These systems are said to be operating synchronously. In systems where two different clock sources are used for these signals, the operation is called asynchronous ...