allegro焊盘尺寸与AntiPad焊盘的理解.doc

Allegro中ThermalreliefPad和AntiPad一直都没有理解ThermalreliefPad和AntiPad的关系,现在弄明白了。具体如下:假设现在要做的板子是四层板子,具体分层如下:Beginlayer:topInternal1:VCCInternal2:GNDEndlayer:bottom假设有通孔类焊盘,,如下图所示,顶层为regularpad底层也为regularpad通孔internal1层即为thermalreliefpad(此处是一般是通过flash焊盘将drill和internal1连接)通孔internal2层即为Antipad(此处一般是通过AntiPad将internal2和drill进行隔离)尺寸:Drill_Size>=Physical_Pin_Size+10mil(~)RegularPad>=Drill_Size+16mil(Drill_Size<50mil)()RegularPad>=Drill_Size+30mil(Drill_Size>=50mil)()RegularPad>=Drill_Size+40mil(Drill为矩形或椭圆形时)(1mm)RegularPad,ThermalRelief,AntiPAD焊盘之间的尺寸关系或公式1、AntiPad直径=ThermalRelief直径=RegularPad+20mil ()2、Soldermask直径=RegularPad+4mil ()3、Flash内径=Drill_Size+16mil()4、Flash外径=Drill_Size+30mil()5、Flash焊盘开口Wed大小: 当Drill_Size<=10mil时:wed=12mil; 当Drill_Size=11~40mil时:wed=15mil; 当Drill_Size=41~70mil时:wed=20mil; 当Drill_Size=71~170mil时:wed=30mil;当Drill_Size>=170mil时:wed=40mil;