On Jan 5, 2018, at 21:28, Luke Kenneth Casson Leighton <[email protected]> wrote: > > still doing these tiny little changes, it's just the way it goes: > every time you look at the board in close zoom, it's like... "hmmm, > yeah that could be improved" and this latest one, it's the (now pair > of) capacitors for the main DDR3 power stabilisation. > > previously this was a single 0805 capacitor lined up vertically. > there was plenty of connecting VIAs down to layer 4 DDR3 1.5v power > plane.... but because there were a MASSIVE array of tracks underneath > the GND pads there were no GND vias. whoops. and when replacing with > two 0603 4.7uF capacitors, i maintained that mistake. > > i decided to turn both 0603 capacitors horizontal and then to beef up > the number of GND vias. this has the unintended side-effect of > drilling quite a lot of holes into the layer 4 DDR3 1.5v power plane > however as the GND vias are at the edge of the plane i consider this > acceptable. i have however made sure that the plane is free of holes > for getting the actual 1.5v power *in* to the plane, if that makes any > sense.
Good stuff. Should make the power supply more stable for the DDR3 RAM chips! > anyway a few more things like this... richardt if you're happy with the > beginning of the HDMI area i'll send the gerbers off straight away. I am happy with the HDMI but I was going to ask about silkscreen on pads--I saw several instances of silkscreen on areas you'll want covered in solder. Sorry I didn't bring it up earlier. Not a problem if you aren't having the silkscreen printed. Your board fab may also do the right thing and move the offending notations. _______________________________________________ arm-netbook mailing list [email protected] http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to [email protected]
