UG-1042
Easy to Use AD4000 Series 16-/18-/20-Bit Precision SAR ADCs User Guide
Rev. E | Page 12 of 25
AC TESTING—HISTOGRAM
The ac testing histogram tests the ADC for the code distribution
for the ac input, computes the mean and minimum/maximum
amplitude and LSB size of the converter. Raw data is captured
and passed to the PC for statistical computations. To perform a
histogram test, click the
Histogram
tab and click
Single Capture
or
Continuous Capture
. Note that an ac histogram needs a
quality signal source applied to the J6 and J10 input connectors.
Figure 22 shows the histogram for a 1 kHz sine wave applied to
the ADC input and illustrates the different measured values for
the data captured.
DC TESTING—HISTOGRAM
More commonly, the histogram is used for dc testing where the
user tests the ADC for the code distribution for dc input, computes
the mean and standard deviation, or transition noise, of the
converter, and displays the results. Raw data is captured and
passed to the PC for statistical computations. To perform a
histogram test, click the
Histogram
tab and click
Continuous
Capture
. Note that a histogram test can be performed without an
external source using a V
REF
/2 (590 Ω resistor divider) at the
ADC input. To test other dc values, apply a source to the J6 and
J10 input connectors. It may be required to filter the signal to
make the dc source noise compatible with that of the ADC.
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98
1-
01
9
Figure 22.
Histogram
Tab, Histogram Captured for Sine Wave
