一些layout会用到的

介质为FR4材料时:75Ω带状线，w=h/8；50Ω带状线，w=h/3；75Ω微带线，w=h；50Ω微带线，w=2h。

·····················································································

许多单片机对电源噪声很敏感,要给单片机电源加滤波电路或稳压器，以减小电源噪声对单片机的干扰。比如，可以利用磁珠和电容组成π形滤波电路，当然条件要求不高时也可用100Ω电阻代替磁珠。

·····················································································

注意高频电容的布线，连线应靠近电源端并尽量粗短，否则，等于增大了电容的等效串联电阻，会影响滤波效果。

·····················································································

1/2盎司厚度的 一般40mil宽可承受1A电流

·····················································································

如果1平方米的铜箔要使其重量为1金衡盎司,也就是31.1035克,则其厚度应该是31.1035/(8.9*100*1000)=35微米,即我们平时所说的做1盎司的PCB板,实际厚度就是1.4mil，即35微米,2盎司就是70微米.

·····················································································

单位是inch

············································································································