M_Card  Design Details
                  ----------------------------

                                                  Original Rev.  6-MAY-1997
                                               Most Recent Rev.  6-MAY-1997


Artwork Order
-------------


Artwork
 Order
 Number           Layers                           Special Stuff
-------    ----------------------------------   -----------------------------
    1      Board_Outline,Target,Dam_3
    2      Signal_1,Pad_1,Pow_1,Target,Dam_1    Thermal_Relief, Clear 25 mil
    3      Signal_2,Pad_2,Pow_1,Target,Dam_2    Thermal_Relief, Clear 25 mil
    4      Silkscreen_1,Target
    5      Solder_Mask_1,Target


Artwork Order Number 1 is the Test Plot of the Board Outline.  It uses
  the Dam_3 layer to hold the "Label" for this plot that goes in the
  target text area.  This label is kept on a private layer so that it
  will not show when the Board Outline is implicitly turn on again during
  the generation of the planes to generate the plane edge relief.

Artwork Order Number 2 is the Component side Ground Plane and Traces
        Dam_1 is used to make the cut between the Digital and Analog planes
        on the Component side.

Artwork Order Number 3 is the Solder side Ground Plane and Traces
        Dam_2 is used to make the cut between the Digital and Analog planes
        on the Solder side.



Gerber File vs Baord Layer

     File Name              Contents                Location in Board Stack
  --------------    ----------------------------   ---------------------------
  ArtWork_01.Grb    Test plot of board outline

  ArtWork_02.Grb    Component side Plane & Traces   Component Side
  ArtWork_03.Grb    Solder side Plane & Traces      Solder Side

  ArtWork_04.Grb    Silkscreen                     On the Component Side

  ArtWork_05.Grb    Solder Mask Comp Side          On the Component Side


The Component Side and Solder Side of this board are almost comleteley
covered by Gnd Planes.  Embedded in this plane are a few traces.  All pins
are either fully buried in the plane (with no thermal relief) or else have
60 mil pads that are fully isolated from the plane by a 12 mil air gap.


Hole Count
----------

          Finished Size       Count
          -------------      -------
                40             828
               106               2
               140              17




The same Aperture Table is used in all plots.  No artwork files need to be
hand edited.  In the Mentor version of the Aperture Table there are a number
of extra apertures defined.  These were all removed in the Aperture Table
that was sent to the manufacturer.


By had move from the DIRAC  [...M_Card] directory to the  /Copy_to_Flop_Dir
directory the following files:


        APERTURE_TABLE_REPORT.TXT   --->   aperture.txt
           DRILL_TABLE_REPORT.TXT   --->      drill.txt
     Manufacture_Instructions.TXT   --->   instruct.txt


COPY_TO_FLOPPY_DIRECTORY.SH   located in  /d_card_uber  is uned to
move Gerber and drill data files from   /pcb/mfg  to the  /Copy_to_Flop_Dir

The "comp file" for M-Card is in  Comp_Comp_Work.txt    This gets directly
directly copied to   /m_card_design/pcb/comps.comps_#