Some things about the SCA design and Magic/Lasi/GDSVU
The SCA design can be viewed and modified with Magic. The original design can be
read-in as CIF and written out as Magic files for the entire design or any
individual cells. A hierarchial design is necessary because of the large number of
The original file from Stuart Kleinfelder was in CIF file format. The original design had a small
fix done to it to add protection diodes to the OP Amp Reference pin. The new design
was named CAL4b. The working terminology for the packaged units is SCA4b. CAL4b is
the 'code' name for Orbit Semiconductor Inc., the two names are synonomus.
There was a problem with the first SCA4 design that caused offset problems.
The cause was evenually traced to a process error in the pad design. This problem was eliminated
in the last fabrication run.
Magic is a free CAD IC layout tool. It was only available for Unix workstations
until about a year ago when someone ported it to Windows. It still needs an X-
windows manager to run but seems to run quite well under Windows.
A major drawback of Magic is that there is no way to get good printouts of a design.
Artworks Conversion Software Co. makes a GDSII viewer that can make good printouts of a
design if the format is GDSII. Magic does not output a very compatable GDS file, at
least one that GDSVU can open, so a work-around I found is to use LASI as a
translater. LASI is another free layout tool that can import GDS and CIF files. It
does this by translating the file format into its native tlc format. Once in this
format it can convert back to the other format. i.e. CIF2tcl and tcl2GDS. GDSVU can
open this sucessfully.