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本帖最后由 dbit 于 2011-10-7 16:40 编辑 - N A) q+ A3 ` `! t4 K
123456sz 发表于 2011-10-5 00:30 ![]()
5 C! Q. g3 C+ I4 }- s- [7 {+ c( z/ R更改铜厚没有反应
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谢谢你帮忙查出问题，另外过孔不需要铜厚，我已去掉，线宽的公式中，没有除铜厚，现修正。( ^- V: O* [) Q6 A
& k3 E* X3 f8 w* L, Q$ C" o, k+ w* q所有计算依据:IPC-2221标准制定;
. d% v! h0 T$ K7 x' B6 a) ?. kIPC-2221标准描述:是由IPC组织制定的关于PCB设计的通用标准,英文名为:
+ A1 j: x- d7 M& Y- q" h. I! S5 `$ j( yGeneric Standard on Printed Board Design( r% Y9 E" Z! P# o4 B
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trace width calc
" S. z9 C2 e3 u3 b- c2 |# m: bArea[mils^2] = (Current[Amps]/(k*(Temp_Rise[deg. C])^b))^(1/c) ( m+ P( x$ O6 b# P6 @. X+ T
Then, the Width is calculated:
$ C3 N8 _* G, }6 r* T: v& ~Width[mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz])
7 w6 Z" h: h. B) ~$ f/ yFor IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725
) t T# y3 E) @6 X& BFor IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
5 F2 p1 Y6 t6 r" s* ^where k, b, and c are constants resulting from curve fitting to the IPC-2221 curves ! ]# [1 A" S" G; X0 ?" l4 e
) [' ]) q% f: I( W0 A/ v3 [' TPCB VIA calculator 7 h6 y9 O" b' F! m
Resistance = Resistivity*Length/Area
9 `! Y) e5 U& O ~, ^Area = pi*(Inner_dia + Plating_thk)*Plating_thk
2 k4 |5 U& J7 J5 ]0 iResistivity = 1.9E-6 Ohm-cm (plated copper)
1 Y1 l2 y" F5 Q3 S# v(plated copper is much more resistive than pure copper) 7 ?% ?' j5 P; }* M
Copper Thermal_Resistivity = 0.249 cm-K/W (at 300K)
9 ]$ K. [ g1 CEst_Ampacity [Amps] = k*(Temp_Rise [deg C])^b*(Area [mils^2])^c % K9 L* D: _9 e
For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
. P& h6 F. u7 i! |1 u/ g我做的一个xls方式的计算式，可以算电流的。4 A& c% r# F2 J( X
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楼主
发表于 2011-10-7 23:04
