kicad-developers team mailing list archive

["Paul \"LeoNerd\" Evans" <leonerd@xxxxxxxxxxxxxx>]

Hi all,

At risk of opening what is a long and contentious subject, I'd like to
start by asking a practical "how should I do X?" question, that will
lead on to one of my main complaints about the way KiCad currently
works and how I think it could be improved.

I am currently making a library part + footprint for a DCDC converter
module - one of those little 2W black brick things. For example

  http://power.murata.com/datasheet?/data/power/ncl/kdc_mee1.pdf

These things come in two physical layouts with identical electronics
inside. In SIL-4 configuration, the pins are

  1=-IN, 2=+IN, 3=-OUT, 4=+OUT

In DIP-8 configuration, the pins are

  1=-IN, 4=+IN, 5=+OUT, 7=-OUT

So my immediate practical question is:

  How should I represent this in KiCad?

Should I

  A) Make a single schematic library symbol for a generic "DC-DC
     converter" whose pin names are IN- IN+ OUT- OUT+ and two
     different footprints whose pin names match.

  B) Make two schematic library symbols with named (or numbered) pins,
     one associated with each footprint?

I find the A) solution nicer because now I only have one schematic
library symbol. Crucially, the upshot here is that I can sketch out my
circuit design *before* I've committed myself to which physical part I
want to use. It's certainly a lot nicer than B), wherein I'd have to
change my schematic if I wanted to use a differently shaped (but
electrically identical) physical part, depending on constraints of the
board's layout or other concerns.

I also find A) nicer because it means that maybe one day in the future
some manufacturer might come up with yet a brand new shape of physical
part, but I can just reuse my existing schematic symbol for this. All
fits in no problem.

<for ease of replies; continued in part 2...>

-- 
Paul "LeoNerd" Evans

leonerd@xxxxxxxxxxxxxx
http://www.leonerd.org.uk/  |  https://metacpan.org/author/PEVANS

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