ADV7183KST Analog Devices Inc, ADV7183KST Datasheet - Page 37

• Manufacturer Part Number: ADV7183KST
• Manufacturer: Analog Devices Inc

Specifications of ADV7183KST

• Adc/dac Resolution: 10b
• Screening Level: Commercial
• Package Type: LQFP
• Pin Count: 80
• Lead Free Status / RoHS Status: Not Compliant

Appendix
BOARD DESIGN AND LAYOUT CONSIDERATIONS
The ADV7183 is a highly integrated circuit containing both preci-
sion analog and high-speed digital circuitry. It has 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
such that high speed and accurate performance are achieved. Figure
30 shows the recommended analog circuit layout.
The layout should be optimized for lowest noise on the ADV7183
power and ground lines by shielding the digital inputs and provid-
ing good decoupling. The lead length between groups of VDD and
GND pins should be minimized to reduce inductive ringing.
Ground Planes
The ground plane should be split into two, one analog and one
digital. They should be joined directly under the ADV7183.
The analog ground return path should be through the digital
(the digital ground is connected to the analog ground and also
the system ground, whereas the analog ground is only connected
to the digital ground; this will ensure only analog current will flow
in the analog ground).
Power Planes
The ADV7183 and any associated analog circuitry should have
its own power planes, referred to as the analog and digital
power planes. These power planes should be connected to the
regular PCB power plane (V
bead. This bead should be located within three inches of the
ADV7183.
The PCB power plane should provide power to all digital logic on
the PC board and the digital power pins on the ADV7183, and
the analog power plane should provide power to all analog power
pins on the ADV7183.
Plane-to-plane noise coupling can be reduced by ensuring that
portions of the regular PCB power and ground planes do not
overlay portions of the analog power plane, unless they can be
arranged so the plane-to-plane noise is common-mode.
CC
) at a single point through a ferrite
Supply Decoupling
For optimum performance, bypass capacitors should be installed
using the shortest leads possible, consistent with reliable operation,
to reduce the lead inductance. Best performance is obtained with
0.1 µF ceramic capacitor decoupling. Each group of power pins
on the ADV71783 must have at least one 0.1 µF decoupling
capacitor to its corresponding ground. These capacitors should
be placed as close as possible to the device.
It is important to note that while the ADV7183 contains cir-
cuitry to reject power supply noise, this rejection decreases with
frequency. If a high-frequency switching power supply is used,
the designer should pay close attention to reducing power sup-
ply noise and consider using a three-terminal voltage regulator
for supplying power to the analog power plane.
Digital Signal Interconnect
The digital inputs and outputs to and from the ADV7183 should
be isolated as much as possible from the analog inputs and other
analog circuitry. Also, these input signals should not overlay the
analog power plane.
Due to the high clock rates involved, long clock lines to and
from the ADV7183 should be avoided to reduce noise pickup.
Any series termination resistors (typically 33Ω) for the digital
inputs should be connected to the high-speed digital outputs.
Analog Signal Interconnect
The ADV7183 should be located as close as possible to the
input connectors to minimize noise pickup and reflections due
to impedance mismatch.
The video input signals should overlay the ground plane, and
not the analog power plane, to maximize the high-frequency
power supply rejection.
Digital outputs, especially pixel data Inputs and clocking sig-
nals, should never overlay any of the analog signal circuitry and
should be kept as far away as possible.
The ADV7183 should have no inputs left floating. Any inputs
that are not required should be tied to ground.
ADV7183