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理解Thermal relief Pad 和Anti Pad的关系

文档创建者:uisrc
浏览次数:7114
最后更新:2018-12-31
一直都没有理解Thermal relief Pad 和Anti Pad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:
Begin layer: top
Internal1: VCC
Internal2: GND
End layer: bottom
假设有通孔类焊盘,所连接的网络为VCC,如下图所示,
顶层为regular pad
底层也为regular pad
通孔internal1层即为thermal relief pad (此处是一般是通过flash焊盘将drill和internal1连接)
通孔internal2层即为Anti pad (此处一般是通过Anti Pad将internal2和drill进行隔离)
TIM图片20181231192016.jpg
尺寸:
Drill_Size >= Physical_Pin_Size+10mil(我们一般取0.25~0.3mm)
Regular Pad >= Drill_Size+16mil(Drill_Size < 50mil) (0.4mm   1.27)
Regular Pad >= Drill_Size+30mil(Drill_Size >= 50mil) (0.76mm   1.27)
Regular Pad >= Drill_Size+40mil(Drill为矩形或椭圆形时) (1mm )
Regular Pad ,Thermal Relief,Anti PAD焊盘之间的尺寸关系或公式
1、Anti Pad直径=Thermal Relief直径=Regular Pad+20mil (我们一般取0.2mm)
2、Soldermask直径=Regular Pad+4mil  (我们一般取0.1mm)
3、Flash内径=Drill_Size+16mil(我们一般取0.5mm)
4、Flash外径=Drill_Size+30mil(我们一般取0.8mm)
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;

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