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dc2071afc
DEMO MANUAL DC2071A
DC590 Data Collection
Due to the relatively low and somewhat unpredictable
sample rate of the DC590, its usefulness is limited to
noise measurement and data collection of slowly moving
signals. A typical data capture and histogram are shown in
Figure 10. To change the default settings for the LTC2373-
18 sequencer in QuikEval click on the Sequence Config.
button. This will open the Sequence Configuration menu
of Figure 11. In this menu, it is possible to set the number
of sequences up to 16, the channel configuration, format
and gain compression setting for each sequence. There
is also a button to return QuikEval to the default DC2071
settings which are optimized for the default hardware
settings of the DC2071A.
To get the best noise performance from the DC2071 it
is recommended to place the demo board in a grounded
metal enclosure filled with tissue paper.
Layout
As with any high performance ADC, this part is sensitive
to layout. The area immediately surrounding the ADC on
the DC2071A should be used as a guideline for placement
and routing of the various components associated with
the ADC. Here are some things to remember when lay-
ing out a board for the LTC2373-18. A ground plane is
necessary to obtain maximum performance. Keep bypass
capacitors as close to supply pins as possible. Use indi-
vidual low impedance returns for all bypass capacitors.
Use of a symmetrical layout around the analog inputs
will minimize the effects of parasitic elements. Shield
analog input traces with ground to minimize coupling
from other traces. Keep traces as short as possible.
Component Selection
When driving a low noise, low distortion ADC such as
the LTC2373-18, component selection is important so
as to not degrade performance. Resistors should have
low values to minimize noise and distortion. Metal film
resistors are recommended to reduce distortion caused
by self heating. Because of their low voltage coefficients,
to further reduce distortion, NP0 or silver mica capacitors
should be used. Any buffer used to drive the LTC2373-18
should have low distortion, low noise and a fast settling
time, such as the LT1469, LT6237, LT6350 or LTC6362.
Figure 10. QuikEval Screen Shot
DC2071A SETUP
