ADV7305AKST Analog Devices Inc, ADV7305AKST Datasheet - Page 49

• Manufacturer Part Number: ADV7305AKST
• Description: IC ENCODER VIDEO 14BIT 64LQFP
• Manufacturer: Analog Devices Inc
• Type: Video Encoderr

Specifications of ADV7305AKST

• Applications: DVD, SD/HD
• Voltage - Supply, Analog: 2.5V
• Voltage - Supply, Digital: 2.5V
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Number Of Dac's: 6
• Adc/dac Resolution: 14b
• Screening Level: Commercial
• Package Type: LQFP
• Pin Count: 64
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

SD ACTIVE VIDEO EDGE
[Subaddress 42h, Bit 7]
When the active video edge is enabled, the first three pixels and
the last three pixels of the active video on the Luma Channel are
scaled in such a way that maximum transitions on these pixels
are not possible. The scaling factors are 1/8 , 1/2 , and 7/8 .
All other active video passes through unprocessed.
BOARD DESIGN AND LAYOUT CONSIDERATIONS
DAC Termination and Layout Considerations
The ADV7304A/ADV7305A contain an on-board voltage refer-
ence. The V
0.1 µF capacitor when the internal V
the ADV7304A/ADV7305A can be used with an external V
AD1580). The R
pins and AGND and are used to control the full-scale output
current and, therefore, the DAC voltage output levels. For
full-scale output, R
values should not be changed. R
full-scale output.
Video Output Buffer and Optional Output Filter
Output buffering on all six DACs is necessary in order to drive
output devices, such as SD or HD monitors. Analog Devices
produces a range of suitable op amps for this application, for
example the AD8061. More information on line driver buffering
circuits is given in the relevant op amp data sheets.
An optional analog reconstruction LPF might be required as an
antialias filter if the ADV7304A/ADV7305A is connected to a
device that requires this filtering. The filter specifications vary
with the application, see Table XXIII.
Input
Mode
SD
SD
PS
PS
HDTV 1
HDTV 2
REV. A
External Filter Cutoff
Oversampling
2
8
1
4
Table XXIII. External Filter Requirements
REF
pin is normally terminated to V
SET
SET
resistors are connected between the R
must have a value of 760 Ω. The R
Frequency Attenuation
>6.5 MHz
>6.5 MHz
>12.5 MHz –50 dB @ 14.5 MHz
>12.5 MHz –50 dB @ 95.5 MHz
>30 MHz
>30 MHz
100 IRE
0 IRE
LOAD
LUMA CHANNEL WITH
ACTIVE VIDEO EDGE
DISABLED
REF
Figure 72. Active Video Edge Functionality Example
has a value of 150 Ω for
is used. Alternatively,
–50 dB @ 20.5 MHz
–50 dB @ 101.5 MHz
–50 dB @ 44.25 MHz
–50 dB @ 118.5 MHz
AA
through a
REF
SET
SET
(e.g.,
–49–
87.5 IRE
12.5 IRE
100 IRE
50 IRE
0 IRE
DAC O/P
LUMA CHANNEL WITH
ACTIVE VIDEO EDGE
ENABLED
–10
–20
–30
–40
–50
–60
Figure 73. Example for Output Filter for SD,
8
Figure 74. Filter Plot for Output Filter for SD,
8
0
1
300R
Oversampling
Oversampling
6.8 H
47pF
GROUP DELAY (sec)
CIRCUIT FREQUENCY RESPONSE – MHz
6.8 H
300R
PHASE (Deg)
ADV7304A/ADV7305A
10
600R
1.8k
MAGNITUDE (dB)
75R
100
36n
30n
24n
18n
12n
6n
0n
BNC O/P
–120
–240
480
360
240
120
0