Datasheet

AD9776/AD9778/AD9779
Rev. A | Page 47 of 56
1. SET INTERPOL
A
TION R
A
TE
2. SET INTERPOLATION FILTER MODE
3. SET INPUT DATA FORMAT
4. SET DATACLK POLARITY TO MATCH INPUT TIMING
0
5361-099
Figure 102. SPI Port Software Window
The default settings for the evaluation board allow the user to
view the differential outputs through a transformer that
converts the DAC output signal to a single-ended signal. On the
evaluation board, these transformers are designated T1A, T2A,
T3A, and T4A. There are also four common-mode transformers
on the board that are designated T1B, T2B, T3B, and T4B. The
recommended operating setup places the transformer and
common-mode transformer in series. A pair of transformers
and common-mode transformers are installed on each DAC
output, so that the pairs can be set up in either order. As an
example, for the frequency range of dc to 30 MHz, it is
recommended that the transformer be placed right after the
DAC. Above DAC output frequencies of 30 MHz, it is
recommended that the common-mode transformer is placed
right after the DAC outputs, followed by the transformer.