封装焊盘尺寸计算

0805封装:
焊盘
焊盘宽度X= 1.20mm,焊盘高度Y = 1.40mm,总长度G = 3.20mm,中心距=2.0mm
Begin Layer(Top层):Regular Pad选择Rectangle,Width=1.20mm,Height=1.40mm;
SOLDERMASK_TOP(绿油层):Regular Pad选择Rectangle,Width=1.2mm+4~20mil(0.1mm~0.5mm),
Height=1.4mm+4~20mil (0.1mm~0.5mm) ;
PASTEMASK_TOP (钢网层) :Regular Pad选择Rectangle,Width=1.2mm,Height=1.4mm;
封装
Place_Bound的尺寸:焊盘的外边缘+10~20mil,线宽不用设置。
丝印的尺寸:比Place_bound略小(0~10 mil),表贴类是贴着Place_Bound的边界。
装配层(Assembly)一般跟丝印层一样
标示符包括装配层Assembly_Top和丝印层Silkscreen_Top两个部分,options里的设置也分两部分

DIP封装:
焊盘
假设元件直插引脚直径为:PHYSICAL_PIN_SIZE,则对通孔焊盘的各尺寸如下表所示:

例:假如引脚直径PHYSICAL_PIN_SIZE =20 mil,Drill Diameter = 32mil,Regular Pad = 48mil,Anti-pad = 68mil,Inner Diameter = 52mil,Outer Diameter = 68mil,Spoke width = 18mil。
顶层(BEGIN LAYER)的设置

  • Regular Pad的Width和Height与Regular Pad的直径 (48 mil) 相同,Geometry选择Circle,Width填入48mil即可;
  • Thermal Pad必须选择Flash,并选择刚制作的热风焊盘TR_68_52,此时会自动弹出Width (68) 和Height (68) ;
  • Anti Pad的Width和Height设置与Thermal Relief相同即可,无论如何,Begin Layer的Thermal Relief和Anti Pad总是比Regular Pad大约20mil (0.5mm) 。

中间层(DEFAULT_INTERNAL)的设置、底层(END_LAYER)的设置与Begin Layer设置相同即可
阻焊层(SOLDERMASK_TOP和SOLDERMASK_BOTTOM),Solder Mask=Regular Pad直径+4~20 mil(焊盘直径越大,这个值也可酌情增大)。
备注:两孔中心距0.6以下则阻焊层一般是Regular Pad+2mil,因为两孔之间的绿油小于3mil板厂就做不了。

SMD IC封装:
焊盘


根据上表公式,AD8510的W = (50mil+15.7mil)/2 = 33mil,PCB焊盘长X = 81mil,引脚间距P = 50mil,脚趾宽度Z = 16mil,PCB焊盘宽Y=24mil

上图是QFN封装(来自于ATmega88PA-MU)
上图中焊盘间距e=0.45mm,焊盘宽度b=0.22mm,焊盘长度L=0.40mm,根据下表可知,焊盘宽度X=0.26mm,外延Tout=0.15mm,内沿Tin=0.05mm。
通常情况下,外延取0.25 mm,内延取0.05 mm。

由上表可知AD8510的W = (50mil+15.7mil)/2 = 33mil,PCB焊盘长X = 81mil,引脚间距P = 50mil,脚趾宽度Z = 16mil,PCB焊盘宽Y=24mil。
参考AD8056的SO8封装尺寸,W=(16+50)/2=33 mil,P= 50mil,Z=(19.2+13.8)/2=17.5 mil,故而X取80 mil,Y取25 mil。

  • Begin Layer(Top层):选择Rectangle,Width = 81mil,Height = 24mil;
  • SOLDERMASK_TOP(绿油层):选择Rectangle,Width = 81mil + 4~20mil (0.1mm~0.5mm) ,Height = 24mil+4~20mil (0.1mm~0.5mm) ;
  • PASTEMASK_TOP (钢网层) :选择Rectangle,Width = 81mil,Height = 24mil;

封装
芯片中心点到PCB焊盘外边界的距离S,2xS=2xD + 48mil,2xD = (228.4mil+244mil)/2,所以D = 118.1mil, S = D + 24mil = 142mil,PCB焊盘长X = 81mil,S-X/2 = 102mil
参考AD8056的SO8封装尺寸,D=(228.4+244)/4=118.1 mil,故而S=142 mil,取140 mil。与2.2.2中重复的部分这里不再赘述。

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转载自www.cnblogs.com/princepeng/p/11392396.html
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