
AD9444
Table 10. Digital Output Coding
VIN+ VIN
Input Span = 2 V p-p (V)
16383
1.000
8192
0
8191
0.000122
0
1.00
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Code
VIN+ VIN
Input Span = 1 V p-p (V)
0.500
0
0.000061
0.5000
Digital Output
Offset Binary (D9D0)
11 1111 1111 1111
10 0000 0000 0000
01 1111 1111 1111
00 0000 0000 0000
Digital Output
Twos Complement (D9D0)
01 1111 1111 1111
00 0000 0000 0000
11 1111 1111 1111
10 0000 0000 0000
EVALUATION BOARD
Evaluation boards are offered to configure the AD9444 in
either CMOS or LVDS mode. Each represents a recommended
configuration for using the device over a wide range of sample
rates and analog input frequencies. These evaluation boards
provide all the support circuitry required to operate the ADC in
its various modes and configurations. Complete schematics and
layout plots follow and demonstrate the proper routing and
grounding techniques that should be applied at the system level.
It is critical that signal sources with very low phase noise
(< 1 ps rms jitter) be used to realize the ultimate performance
of the converter. Proper filtering of the input signal, to remove
harmonics and lower the integrated noise at the input, is also
necessary to achieve the specified noise performance.
The evaluation boards are shipped with an ac to 6 V dc power
supply. The evaluation boards include low dropout regulators to
generate the various dc supplies required by the AD9444 and its
support circuitry. Separate power supplies are provided to iso-
late the DUT from the support circuitry. Each input configura-
tion can be selected by proper connection of various jumpers
Both the LVDS and CMOS versions of the evaluation board are number HSC-ADC-EVALA-SC). The kit includes a high speed
memory chip (user upgradeable to 256K samples). Software is
PC via the USB port. This software also includes a behavioral
model of the AD9444 and many other high speed ADCs.
. The ADIsimADC software
behavioral modeling technology. This allows rapid comparison
without hardware evaluation boards.
directly.
data and the DCO output clock of the AD9444.