①线
一般情况下,信号线宽为0.3mm(12mil),电源线宽为0.77mm(30mil)或1.27mm(50mil);线与线之间和线与焊盘之间的距离大于等于0.33mm(13mil),实际应用中,条件允许时应考虑加大距离;
布线密度较高时,可考虑(但不建议)采用IC脚间走两根线,线的宽度为0.254mm(10mil),线间距不小于0.254mm(10mil)。特殊情况下,当器件管脚较密,宽度较窄时,可按适当减小线宽和线间距。
②焊盘(PAD)
焊盘(PAD)与过渡孔(VIA)的基本要求是:盘的直径比孔的直径要大于0.6mm;例如,通用插脚式电阻、电容和集成电路等,采用盘/孔尺寸 1.6mm/0.8mm(63mil/32mil),插座、插针和二极管1N4007等,采用1.8mm/1.0mm(71mil/39mil)。实际应用中,应根据实际元件的尺寸来定,有条件时,可适当加大焊盘尺寸;
PCB板上设计的元件安装孔径应比元件管脚的实际尺寸大0.2~0.4mm左右。
③过孔(VIA)
一般为1.27mm/0.7mm(50mil/28mil);
当布线密度较高时,过孔尺寸可适当减小,但不宜过小,可考虑采用1.0mm/0.6mm(40mil/24mil)。
④焊盘、线、过孔的间距要求
PAD and VIA : ≥ 0.3mm(12mil)
PAD and PAD : ≥ 0.3mm(12mil)
PAD and TRACK : ≥ 0.3mm(12mil)
TRACK and TRACK : ≥ 0.3mm(12mil)
密度较高时:
PAD and VIA : ≥ 0.254mm(10mil)
PAD and PAD : ≥ 0.254mm(10mil)
PAD and TRACK : ≥ 0.254mm(10mil)
TRACK and TRACK : ≥ 0.254mm(10mil)