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本帖最后由 dbit 于 2011-10-7 16:40 编辑
9 g; b5 d# Q8 U! j123456sz 发表于 2011-10-5 00:30 ![]() , p3 h: ^5 p# m/ R* P P, i
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。
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! T8 k& z- Q# ]所有计算依据:IPC-2221标准制定;
9 a6 ?: {' p$ S: L* T/ F0 n$ _IPC-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:% h% r. b( o7 I/ D: A" g- }/ n
Generic Standard on Printed Board Design
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trace width calc
; |- }/ E) a+ [: C. q# ?. G* }Area[mils^2] = (Current[Amps]/(k*(Temp_Rise[deg. C])^b))^(1/c)
3 K: A$ ^- t, t+ mThen, the Width is calculated: / O, U. [; t# d ~
Width[mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz]) 4 a. b0 q3 n. z" {! L4 x
For IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725
$ t/ {, f6 f: w+ R9 jFor IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725 ^, }% E! E9 j* f& `5 {
where k, b, and c are constants resulting from curve fitting to the IPC-2221 curves
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PCB VIA calculator
+ \( z o! L& e8 [. \. `" O+ x5 {+ Y3 uResistance = Resistivity*Length/Area 6 w( `# S _0 N& b! v7 r
Area = pi*(Inner_dia + Plating_thk)*Plating_thk
$ k# K8 ^' V1 ^/ J2 [/ Q! NResistivity = 1.9E-6 Ohm-cm (plated copper)
" v2 H2 @7 i, J; L3 m. ?+ P(plated copper is much more resistive than pure copper) ! L1 h/ [" n; |4 E3 G% Y
Copper Thermal_Resistivity = 0.249 cm-K/W (at 300K) . j# z0 s9 {; q [
Est_Ampacity [Amps] = k*(Temp_Rise [deg C])^b*(Area [mils^2])^c
2 P- `' j& p/ A* i& u; q/ o" [For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
4 b2 u. Y% \7 N我做的一个xls方式的计算式，可以算电流的。
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楼主
发表于 2011-10-7 23:04
