adv7310 Analog Devices, Inc., adv7310 Datasheet - Page 55

• Manufacturer Part Number: adv7310
• Description: Multiformat 216 Mhz Video Encoder With Six Nsv 12-bit Dacs
• Manufacturer: Analog Devices, Inc.

BOARD DESIGN AND LAYOUT CONSIDERATIONS
DAC Termination and Layout Considerations
The ADV7310/ADV7311 contain an on-board voltage reference.
The ADV7310/ADV7311 can be used with an external V
(AD1580).
The R
AGND and are used to control the full-scale output current and
therefore the DAC voltage output levels. For full-scale output,
R
be changed. R
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 amps’ data sheets.
An optional analog reconstruction low-pass filter (LPF) may be
required as an anti-imaging filter if the ADV7310/ADV7311 is
connected to a device that requires this filtering.
The filter specifications vary with the application.
Application Oversampling (MHz)
SD
SD
PS
PS
HDTV
HDTV
REV. A
SET
must have a value of 3040 Ω. The R
SET
resistors are connected between the R
Table XVI. External Filter Requirements
LOAD
2×
16×
1×
8×
1×
2×
has a value of 300 Ω for full-scale output.
Cutoff
Frequency Attenuation
>6.5
>6.5
>12.5
>12.5
>30
>30
SET
values should not
–50 dB @ (MHz)
20.5
209.5
14.5
203.5
44.25
118.5
SET
pins and
REF
–55–
OUTPUT
DAC
–10
–20
–30
–40
–50
–60
–70
–80
Figure 55. Example of Output Filter for SD,
16 × Oversampling
Figure 56. Filter Plot for Output Filter for SD,
16 × Oversampling
0
1M
600
GROUP DELAY (sec)
10 H
22pF
CIRCUIT FREQUENCY RESPONSE
10M
600
FREQUENCY (Hz)
ADV7310/ADV7311
560
3
4
PHASE (Deg)
100M
560
MAGNITUDE (dB)
1
75
1G
BNC
OUTPUT
0
–30
–60
–90
–120
–150
–180
–210
–240
24n
21n
18n
15n
12n
9n
6n
3n
0