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Date: Sat, 5 Oct 2013 21:43:23 -0400
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Subject: Re: [geda-user] polygons, arcs and footprints
From: Evan Foss <evanfoss AT gmail DOT com>
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The microphone is an ADMP441. They use a ring round the input port to
seal between the audio input of the microphone and the PCB.

On Sat, Oct 5, 2013 at 2:49 AM, onetmt <onetmt AT gmail DOT com> wrote:
> Il 04/10/2013 23:56, Evan Foss ha scritto:
>> Hi folks,
>>
>> I am trying to make a footprint for an LTC3441. The bottom pad is a
>> polygon. I know they are not possible in PCB footprints but does
>> anyone have a good way to emulation one?
>
> For other components - for instance the BSC159 mosfet by Infineon - I
> used several square pads partially overlapped, in order to get the right
> "polygonal" pad. But in your case, imho, you should use a "normal"
> footprint and then design the polygons on layer, placing vias also on
> central powerpad as indicated in datasheet.
>
>>
>> Also I am trying to use a MEMS microphone that uses a ring to seal it
>> to the PCB. Again I know that does not exist but is there a way around
>> it?
>
> It's difficult to say without knowing the component, but you can obtain
> a ring - well, a sort of - by using appropriate clearance around an
> "octagon" pad and placing a rectangle, maybe on a ground layer, around it.
>
>>
>> -Evan
>>
>
>
> --
> Hofstadter's Law:
> "It always takes longer than you expect, even when you take into account
> Hofstadter's Law."



-- 
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