高速PCB 阻抗匹配问题请教

dylink_lin

现在遇到的难题: PCB板上面有十几对差分线,要求阻抗100OHM, 传输速度2Gbps;

* W5 U7 n" l' s# J+ C; b我现在将差分线线宽设置为0.25mm, 间距0.25mm,板层设置为TOP, GND,POWER,BOTTOM, 不知是否正确?要将差分对阻抗控制在100OHM, 差分线线宽, 厚度,四层板的厚度应该如何设置? 请版主及各位高手帮忙!

michaelw_wang

you need to specify the hight between top/gnd, and bottom/power, to do the calculation.

- a' \" C- o- e6 n! c& v6 Anormally, if the hight is 5mil, trace width is 5mil, gap between two signals in one pair is 8mil, the differential impedance is 100 Ohm.

frankyon

差分对走多少阻抗软件可以计算出来!
但是到其他信号或者地的距离如何求得??

calen

差分对阻抗软件可以用polar SI 80000计算！

fenqinyao

原帖由 michaelw_wang 于 2008-6-25 06:53 发表
. \2 s( J6 r# x" s+ l3 ~- Fyou need to specify the hight between top/gnd, and bottom/power, to do the calculation.

normally, if the hight is 5mil, trace width is 5mil, gap between two signals in one pair is 8mil, the differe ...

! t$ Q' l% ~4 s* J通过计算，阻抗为105

wdckill

具体计算要根据各生产厂家的参数来设计,同样都是100OHM,但线宽与线距要求是不一样的,我们一般根据SI8000来计算

jasonlu

差分对阻抗软件可以用polar SI 80000计算！具体参数要请教板厂做的技术跟材质了

mzsuper

基本同意你的经验值！楼主还是给个stackup给大家，大家才好帮你算呀！
  _1 O4 K: ^9 K  o板厂不同的core不同的PP介电常数也不一样！阻抗就不一样！
1 [! q7 a2 b  U9 Q* Y" |: j4 ]你以100为试算值！然后允许板厂trace wide and space 在+-1mil内调节
就好了

dylink_lin

用SI8000大概计算一下