User Guide

Chapter 10 Preparing Your Design for Board Layout
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The following rules in the
.xpk file will implement this:
DIP*
CC* -CC
Note that the DIP* rule is empty; it matches package
classes such as DIP14, but there is no resulting
replacement string.
The LCC* rule matches all strings that start with LCC, so
it will match package classes such as LCC20 and LCC28. It
appends the string
-CC to the COMPONENT (or PART) name.
Back Annotation
During the course of layout generation, a design can
undergo changes that make the design information in the
PCB layout database inconsistent with that in the
schematic database. When this occurs, the schematic must
be back annotated with the design changes made during
layout to resynchronize the schematic and layout data.
Design changes are usually documented as Engineering
Change Orders (ECOs). Design changes from the layout to
the schematic are called Backward ECOs because the
direction of the change is opposite to the regular flow of
design data.
PSpice Schematics supports the following types of
backward ECOs:
• changing the reference designator of a part
• swapping two gates
• swapping two pins
If any of the other ECO operations are present, PSpice
Schematics logs the warning and displays them as
“Unsupported function” messages. You need to make the
changes manually for any of the unsupported functions
listed in the back annotation log. Back annotation
messages are logged in the same manner as other PSpice
Schematics errors and warnings.
You can automatica
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ECOs from ECO files generated by:
PADS
CADSTAR
Tango
Protel
SCICARDS