Erot
Tämä näyttää erot valitun ja nykyisen version kesken tästä sivusta.
|
ohjeita:design_rules [2015/04/08 00:22] |
ohjeita:design_rules [2015/04/08 00:24] (nykyinen) |
||
|---|---|---|---|
| Rivi 1: | Rivi 1: | ||
| + | Track-to-track / pad-to-pad / pad-to-track clearance 8 mils (0.20 mm) | ||
| + | Track width 8 mils (0.20 mm) | ||
| + | |||
| + | Pad minimum annular ring 12 mils (0.30 mm) | ||
| + | |||
| + | These are minimum values. Always use largest sizes possible. Increase pad and track sizes individually when there is room for extra. 12 mil track/clearance and 16 mil annular ring recommended for most of the PCB. | ||
| + | |||
| + | You can try to do stuff below these minimum limits, but yield goes down very quickly and you have to be extra careful. | ||
| + | |||
| + | Annular ring is especially important in through-plated boards due to the tenting process - photoresist film must have enough area on all sides of the pad to adhere to, and you need to have extra for alignment mismatch. Sacrifice pad-to-pad / pad-to-track clearance on round pads to get larger pads - 6 mil / 0.15 mm clearance is doable in pin header / via rows. If you can ensure 12-16 mil (0.30-0.40 mm) annular ring by doing that, it's all good. | ||
| + | |||
| + | Use 18µm copper clad when you have used extended areas of 8 mil (0.20 mm) work to improve etching resolution. If you through-hole plate your boards, use 18 µm clad even with mainly 10 mil (0.25 mm) boards, because the plating increases the copper thickness by about 15 µm. | ||