//  file:  switch_328_pin_geom
//
//  Original Date:   2-Sept-2014
//   Current Date:   17-Jan-2017
//
//  This geometry is for the  BCM53128  Broadcom switch.
//
//
//    This is the "New Version" with a straight forward
//    Solder Mask and Solder Stencil.
//
//
//    This is a 256 pin part with 64 pins per side.
//
//    The Exposed Pad in the middle of this chip is soldered
//    to the PCB's Thermal Ground Land.
//
//    The Thermal Land is connected to the PCB's internal
//    Ground Planes via 72 Thermal/Ground Plated Through Holes.
//
//    The Thermal Ground Land is 10.0 mm by 9.0 mm  and is on
//    both the Top Side and Bottom Side of the card.  On the
//    Bottom Side it is used as the Ground connection for some
//    of this chip's ByPass Capacitors.
//
//    Note that the copper for the Thermal Land on the top side
//    of the card is included in this Geometry as an explicit
//    Polygon  on layer  BREAKOUT_1  and not as part of a pin
//    definition.   The copper for the Thernal Land on the back
//    side of the card  (opposite side from where the chip is
//    mounted)  is included as a Polygon on the layer
//    Sheet_Dielectric_1  as this layer is setup for special
//    use with the Hub design.
//
//
//    This is a  256 eLQFP  package.
//
//    The pin pitch is  0.40 mm
//
//    The width of the pins is  0.18 mm nominal
//
//    The edges of the plastic package are  28.00 mm  square.
//
//    The far edges of the pins are  30.00 mm  square.
//
//    The size of the IC's Exposed Pad is  8.79mm  by  7.62 mm.
//
//      As layed out here  8.79 mm  is horizontal along the pin 1-64 direction
//                and the  7.62 mm  is vertical along the 65-128 direction.
//
//    This is based on  Broadcom Solder Guidelines Packaging  AN200
//
//      for now I will make the pin pads  0.20 mm  by  1.60 mm.
//
//      For now I will make the external edges of the pin pads
//      be 31.00 mm apart and square.
//
//
//
//  Recall,  we will use the  BCM53128  not the  BCM53128V.
//
//
//  See the Paste_Mask file and the Solder_Mask files for details
//  of these aspects of the layout,  e.g. percent solder paste coverage.
//
//
//  This geometry has been written with pin #1 in the lower
//  left-hand corner  aka  the South-West  corner.
//
//
//  The SMD pads are setup as 0.20 mm wide.
//  The SMD pads are setup as 1.60 mm long.
//
//  This gives 29.40 mm pad center to opposite edge pad center
//          or 14.70 mm pad center to package center.
//
//  First define 3 SMD pad pinstacks and then start the 256 pin geometry.
//


$abort_enable = @false;
$$lock_windows(@on) ;
$$snap_diagonal(@off) ;
$$snap_orthogonal(@off) ;