adv7342 Analog Devices, Inc., adv7342 Datasheet - Page 66

• Manufacturer Part Number: adv7342
• Description: Multiformat Video Encoder Six, 11-bit, 297 Mhz Dacs
• Manufacturer: Analog Devices, Inc.

ADV7342/ADV7343
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0
1M
0
1M
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1
GROUP DELAY (Seconds)
GROUP DELAY (Seconds)
Figure 87. Output Filter Plot for SD, 16× Oversampling
Figure 89. Output Filter Plot for HD, 4× Oversampling
Figure 88. Output Filter Plot for ED, 8× Oversampling
GROUP DELAY (Seconds)
CIRCUIT FREQUENCY RESPONSE
CIRCUIT FREQUENCY RESPONSE
CIRCUIT FREQUENCY RESPONSE
10M
10M
FREQUENCY (Hz)
FREQUENCY (MHz)
FREQUENCY (Hz)
10
MAGNITUDE (dB)
100M
100M
MAGNITUDE (dB)
MAGNITUDE (dB)
PHASE (Degrees)
100
(Degrees)
PHASE
(Degrees)
PHASE
1G
1G
480
400
320
240
160
80
0
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0
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200
120
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18n
16n
14n
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10n
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2n
0
24n
21n
18n
15n
12n
9n
6n
3n
0
Rev. 0 | Page 66 of 88
PRINTED CIRCUIT BOARD (PCB) LAYOUT
The ADV7342/ADV7343 are highly integrated circuits
containing both precision analog and high speed digital
circuitry. They have been designed to minimize interference
effects on the integrity of the analog circuitry by the high speed
digital circuitry. It is imperative that these same design and
layout techniques be applied to the system-level design so that
optimal performance is achieved.
The layout should be optimized for lowest noise on the
ADV7342/ADV7343 power and ground planes by shielding the
digital inputs and providing good power supply decoupling.
It is recommended to use a 4-layer printed circuit board with
ground and power planes separating the signal trace layer and
the solder side layer.
Component Placement
Component placement should be carefully considered to
separate noisy circuits, such as clock signals and high speed
digital circuitry from analog circuitry.
The external loop filter components and components connected
to the COMP, V
possible to and on the same side of the PCB as the ADV7342/
ADV7343. Adding vias to the PCB to get the components closer
to the ADV7342/ADV7343 are not recommended.
It is recommended that the ADV7342/ADV7343 be placed as
close as possible to the output connector, with the DAC output
traces as short as possible.
The termination resistors on the DAC output traces should be
placed as close as possible to and on the same side of the PCB as
the ADV7342/ADV7343. The termination resistors should
overlay the PCB ground plane.
External filter and buffer components connected to the DAC
outputs should be placed as close as possible to the ADV7342/
ADV7343 to minimize the possibility of noise pickup from
neighboring circuitry, and to minimize the effect of trace
capacitance on output bandwidth. This is particularly important
when operating in low drive mode (R
Power Supplies
It is recommended that a separate regulated supply be provided
for each power domain (V
optimal performance, linear regulators rather than switch mode
regulators should be used. If switch mode regulators must be
used, care must be taken with regard to the quality of the output
voltage in terms of ripple and noise. This is particularly true for
the V
individually connected to the system power supply at a single
point through a suitable filtering device, such as a ferrite bead.
AA
and PV
DD
REF
power domains. Each power supply should be
, and R
SET
AA
, V
pins should be placed as close as
DD
, V
DD_IO
SET
= 4.12 kΩ, R
, and PV
DD
). For
L
= 300 Ω).