UG-076
Evaluation Board User Guide
Rev. A | Page 12 of 16
OUTPUT DRIVER WINDOW
The output driver window shown in Figure 22 is accessed by
clicking any of the numbered triangular output driver symbols
on the right side of the main window (see Figure 21).
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Figure 21. Driver Symbol
08
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6-
0
17
Figure 22. Output Driver Window
It is important to power down unused outputs on the evaluation
board because they can be a major source of unwanted spurs.
LVPECL and CMOS outputs have different termination require-
ments, and OUT9 through OUT11 have been terminated
differently from OUT0 through OUT8.
OUT0 through OUT8 are ac-coupled with 200 Ω pull-down
resistors on each output. This termination scheme is ideal for
LVPECL drivers. However, this scheme degrades the CMOS
driver performance. Improved CMOS driver performance is
achieved by removing the 200 Ω pull-down resistors.
OUT9 though OUT11 have no termination resistors, and are
ideally configured for CMOS operation. If the user wants to use
these drivers in LVPECL mode, pull-down resistors must be
added to the board. If the user wants to put 50 Ω termination at
the SMA connectors of OUT9 through OUT11, add series
decoupling capacitors so that the termination on OUT9
through OUT11 is identical to OUT0 through OUT8.
DEBUG WINDOW
The
Debug
window shown in Figure 23 is accessed by clicking
the
Debug
option from the
View
menu.
The
Serial I/O
section of this window is a convenient way to
read and write registers directly.
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018
Figure 23.
Debug
Window
