MC44722AVFU Freescale, MC44722AVFU Datasheet - Page 11

• Manufacturer Part Number: MC44722AVFU
• Manufacturer: Freescale

Specifications of MC44722AVFU

• Adc/dac Resolution: 10b
• Screening Level: Commercial
• Package Type: LQFP
• Pin Count: 48
• Lead Free Status / RoHS Status: Not Compliant

"CVBS and S-VIDEO" or "YCbCr" Outputs
The internal digital video signals drive 10-bit D/A converters. Converter outputs are bidirectional current
sources where the current is proportional to the digital data with reference to the IBIAS reference current.
The pins CVBS/Cb, Y and C/Cr are the respective composite, Luma and Chroma or Y/Cb/Cr signal current
source pins. Each of the DACs can drive 75ohm load resister.
User can select 1 sets of signals from the above 2 signal sets (CVBS/Y/C or Y/Cb/Cr ).
(see "Application Diagram" and "sub-address register descriptions".)
In Y/Cr/Cb analog component output mode, user can select one of the component interface level , Beta Cam
or M2 format ( see sub-address register 6E ).
Bias Current Gain
DACs can be switched off through serial bus control to reduce power consumption. Both outputs of unused
DACs should be connected to ground through a resister to avoid charge buildup.
Chroma / Luma Encoding
The DVE de-multiplexes the 4:2:2 digital video data stream.
The de-multiplexed Y or Luma samples are interpolated at the clock rate. Offset compensation is then
added, next any VBI signals consisting of Closed-Caption, CGMS and WSS are added to the appropriate
lines, then finally composite sync pulses are added to the Luma signal.(see figure 14.)
De-multiplexed component color CB and CR samples are interpolated at the clock rate.
The Luma and Chroma Interpolation filter compensate for the sin(x)/x attenuation to on chip D/A
converter and simplify the output filter and allows more accurate encoding. A set of 3 different filters is
available for each Luma and Chroma filtering. And user can select within these filters to fit a wide
variety of applications. (see figure 12 and 13, and sub-address resister 6F )
The DVE generates the necessary subcarrier color frequency for PAL or NTSC encoding from the 27Mhz
system clock. This color subcarrier is then modulated by the base band component color CB and CR
signals to create the video Chroma signal. (see figure 15.)
A 7.5 IRE pedestal is added for the 60Hz field rate. This can be added for the 50Hz field rate through
serial bus control.
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-48
-3
-6
-9
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0
0
Fig. 12 Luma Filtering Including DAC Attenuation
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f3 = 2.5MHz
This document contains information on a new product. Specifications and information herein are subject to change without notice.
3
4
(see sub-address register descriptions)
f2 = 5MJz
Frequency [MHz]
5
6
7
f1 = 6MHz
Freescale Semiconductor, Inc.
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For More Information On This Product,
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Go to: www.freescale.com
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Fig. 13 Chroma Filtering
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f3 = 1.5MHz
f2 = 2.5MHz
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f1 = 3MHz
Frequency [MHz]
5
MC44722A/3A Rev 0.05 07/15/98
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