观热点:Cadence PCB设计使用笔记分享?


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四、高速PCB设计知识(略)

五、建立元件库: 通孔焊盘的设计: 1、定义:类型Through,中间层(fixed),钻孔Drill/slot(圆形,内壁镀锡plated,尺寸) 2、层的定义:BEGIN Layer(Top)层:REGULAR-PAD < THERMAL-PAD = ANTI-PAD END LAYER(同BEGIN,常用copy begin layer, then paste it) TOP SOLDERMASK:只定义REGULAR-PAD ,大于(Begin layer层regular-pad,约为1.1~1.2倍) BOTTOM SOLDERMASK(同Top soldermask,常用Top soldermask, then paste it) 例1 //--------------------------------------------------------------------------------------- Padstack Name: PAD62SQ32D *Type: Through *Internal pads: Fixed *Units: MILS Decimal places: 4 Layer Name Geometry Width Height Offset (X/Y) Flash Name Shape Name ------------------------------------------------------------------------------------------------------------------ *BEGIN LAYER *REGULAR-PAD Square 62.0000 62.0000 0.0000/0.0000 *THERMAL-PAD Circle 90.0000 90.0000 0.0000/0.0000 *ANTI-PAD Circle 90.0000 90.0000 0.0000/0.0000 *END LAYER(同BEGIN,常用copy paste) DEFAULT INTERNAL(Not Defined ) *TOP SOLDERMASK *REGULAR-PAD Square *75.0000 75.0000 0.0000/0.0000 *BOTTOM SOLDER MASK *REGULAR-PAD Square *75.0000 75.0000 0.0000/0.0000 TOP PASTEMASK(Not Defined ) BOTTOM PASTEMASK(Not Defined ) TOP FILMMASK(Not Defined ) BOTTOM FILMMASK(Not Defined ) NCDRILL 32.0000 Circle-Drill Plated Tolerance: +0.0000/-0.0000 Offset: 0.0000/0.0000 DRILL SYMBOL Square 10.0000 10.0000 ---------------------------------------------- 表贴焊盘的设计: 1、定义,类型single,中间层(option),钻孔(圆形,内壁镀锡plated,尺寸一定为0) 2、层的定义:BEGIN Layer(Top)层:只定义REGULAR-PAD TOP SOLDERMASK:只定义REGULAR-PAD ,大于(Begin layer层regular-pad,约为1.1~1.2倍) 例2 ------------------------------------------------ Padstack Name: SMD86REC330 *Type: Single *Internal pads: Optional *Units: MILS Decimal places: 0 Layer Name Geometry Width Height Offset (X/Y) Flash Name Shape Name ------------------------------------------------------------------------------------------------------------------ *BEGIN LAYER *REGULAR-PAD Rectangle 86 330 0/0 THERMAL-PAD Not Defined ANTI-PAD Not Defined END LAYER(Not Defined ) DEFAULT INTERNAL(Not Defined ) *TOP SOLDERMASK *REGULAR-PAD Rectangle 100 360 0/0 BOTTOM SOLDERMASK(Not Defined ) TOP PASTEMASK(Not Defined ) BOTTOM PASTEMASK(Not Defined ) TOP FILMMASK(Not Defined ) BOTTOM FILMMASK(Not Defined ) NCDRILL(Not Defined ) DRILL SYMBOL Not Defined 0 0 ------------------------------------------ 手工建立元件(主要包含四项:PIN;Geometry:SilkScreen/Assembly;Areas:Boundary/Height;RefDes:SilkScreen/Display) 注意:元件应放置在坐标中心位置,即(0,0) 1、File ew..package symbol 2、设定绘图区域:SetupDrawing size...Drawing parameter... 3、添加pin:选择padstack ,放置,右排时改变text offset(缺省为-100,改为100)置右边 4、添加元件外形:(Geometery) *丝印层Silkscreen:AddLine(OptionActive:package geometery;subclass:silkscreen_top) *装配外框Assembly:AddLine(OptionActive:package geometery;subclass:Assembly_top) 5、添加元件范围和高度:(Areas) *元件范围Boundary:SetupAreaspackage boundary....Add Line(OptionActive Class:Package geometry;subclass:Package_bound_top) *元件高度Height:SetupAreaspackage Height....Add Line(OptionActive Class:Package geometry;subclass:Package_bound_top) 6、添加封装标志:(RefDes)LayoutLabelsResDs...) *底片用封装序号(ResDes For Artwork):Pin1附近(...RefDes:Silkscreen_Top) *摆放用封装序号(ResDes For Placement):封装中心附近(...RefDes:Display_Top) *封装中心点(Body center):指定封装中心位置(AddTextPackage Geometery:Boby_centre) 7、建立Symbol文件:FileCreate Symbol 利用向导建立

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