[sdiy] PCB CAD woes

[Tom Bugs]

I disagree! Certainly for 'big' SMD (SOIC and 0805 typical) - neat as 
anything /// maybe partly practice.
Despite being more metric at heart, I do all to 0.05" grid with a few 
0.025" and an occasional smattering of 0.0125".
Things line up lovely and neat in general! Compensation caps right 
across pins, resistor summers with tiny lengths to the summing nodes! 
And mainly just working on the 1 side with V+ and V- on the bottom - 
easy to plop decoupling caps in just the right place too.
Much of this is practice though..

Ought to try smaller sometime, but I've got nicely set up now for this 
route and reckon it is an 'ain't broke, don't fix' scenario for now.

On 02/10/2015 18:23, Tom Wiltshire wrote:
> Surface mount packages of all types are a nightmare, imho. Unlike through-hole parts, they don't fit on any overall grid. Through-hole parts you can fit on a 0.1" grid. Occasionally, shifting things by a 0.05" here or there helps tidy up.
>
> SMDs are the exact opposite. Even if you want to line them up, you can't. The tracks go all over the place. Spacings aren't consistent. The devices come in a bewildering array of packages, none of which have any common multiples.
>
> Electronics was always a mess, what with there being no real decision made whether we were in imperial or metric (6.35mm shaft or 6mm? 0.1" or 2.5mm? etc etc), but SMD made it a hundred times worse, since the little errors tend to matter much more at that scale.
>
> I commiserate.
>
> Tom
>
>
> On 2 Oct 2015, at 18:02, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
>
>> Surface mount SSOP packages with either 0.65mm (0.0256 inch) or 0.635mm (0.025 inch) pitch.  Who's bright idea was that!?!?
>>
>> Have just laid out a board full of different SSOP packages and now have to redo half of the footprints because they're "slightly" out :-(
>>
>> -Richie,
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>

-- 
BugBrand LTD
UK company No. 07199808
VAT No. GB 988 2629 57
1 Ninetree Hill
BRISTOL BS1 3SB
United Kingdom
www.bugbrand.co.uk