ADA4412-3ARQZ-RL Analog Devices Inc, ADA4412-3ARQZ-RL Datasheet - Page 9

• Manufacturer Part Number: ADA4412-3ARQZ-RL
• Description: IC,TV/VIDEO CIRCUIT,TV/Video Filter,SSOP,20PIN,PLASTIC
• Manufacturer: Analog Devices Inc
• Type: Video Filterr

Specifications of ADA4412-3ARQZ-RL

• Applications: Set-Top Boxes, Video Players
• Mounting Type: Surface Mount
• Package / Case: 20-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

THEORY OF OPERATION
The ADA4412-3 is an integrated video filtering and driving
solution that offers variable bandwidth to meet the needs of a
number of different video resolutions. There are three filters
targeted for use with component video signals. The filters
have selectable bandwidths that correspond to the popular
component video standards. Each filter has a sixth-order
Butterworth response that includes group delay optimization.
The group delay variation from 1 MHz to 36 MHz in the
36 MHz section is 7 ns, which produces a fast settling pulse
response.
The ADA4412-3 is designed to operate in many video environ-
ments. The supply range is 5 V to 12 V, single supply or dual
supply, and requires a relatively low nominal quiescent current
of 15 mA per channel. In single-supply applications, the PSRR
is greater than 60 dB, providing excellent rejection in systems
with supplies that are noisy or under-regulated. In applications
where power consumption is critical, the part can be powered
down to draw typically 10 μA by pulling the DISABLE pin to
the most positive rail. The ADA4412-3 is also well-suited for
high encoding frequency applications because it maintains a
stop-band attenuation of over 40 dB to 400 MHz.
The ADA4412-3 is intended to take dc-coupled inputs
from an encoder or other ground referenced video signals.
The ADA4412-3 input is high impedance. No minimum or
maximum input termination is required, though input
terminations above 1 kΩ can degrade crosstalk performance
at high frequencies. No clamping is provided internally. For
applications where dc restoration is required, dual supplies
work best. Using a termination resistance of less than a few
hundred ohms to ground on the inputs and suitably adjusting
the level-shifting circuitry provides precise placement of the
output voltage.
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For single-supply applications (V
range extends from 100 mV below ground to within 2.0 V of
the most positive supply. Each filter input includes level-shifting
circuitry. The level-shifting circuitry adds a dc component to
ground-referenced input signals so that they can be reproduced
accurately without the output buffers hitting the negative rail.
Because the filters have negative rail input and rail-to-rail
output, dc level shifting is generally not necessary, unless
accuracy greater than that of the saturated output of the driver
is required at the most negative edge. This varies with load but
is typically 100 mV in a dc-coupled, single-supply application. If
ac coupling is used, the saturated output level is higher because
the drivers have to sink more current on the low side. If dual
supplies are used (V
dual-supply applications, the level-shifting circuitry can be used
to take a ground referenced signal and put the blanking level at
ground while the sync level is below ground.
The output drivers on the ADA4412-3 have rail-to-rail output
capabilities with 6 dB gain. Each output is capable of driving
two ac- or dc-coupled, 75 Ω source-terminated loads. If a large
dc output level is required while driving two loads, ac coupling
should be used to limit the power dissipation.
S−
< GND), no level shifting is required. In
S−
= GND), the input voltage
ADA4412-3