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Message-ID: <5253B271.5020302@gmail.com>
Date: Tue, 08 Oct 2013 09:21:21 +0200
From: onetmt <onetmt AT gmail DOT com>
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To: geda-user AT delorie DOT com
Subject: Re: [geda-user] polygons, arcs and footprints
References: <CAM2RGhTKEi4GFb3_sYV8FJRfqr0GTzWfpk28vQ-bDLoQpjvXyQ AT mail DOT gmail DOT com> <524FB65F DOT 9050604 AT gmail DOT com> <CAM2RGhSqy81ZMCjomOkbVCiX9nczAmiVwnhL_DYrBoCYDnqeyw AT mail DOT gmail DOT com> <5253AEAD DOT 6050900 AT gmail DOT com>
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Il 08/10/2013 09:05, onetmt ha scritto:
> Il 06/10/2013 03:43, Evan Foss ha scritto:
>> 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.
> 
> You cold give this example a try; maybe, you could also refine the
> design in order to avoid the sharp edges (I will send you also the basic
> trigonometry I used, in case you would).
> 
...and, sorry: clearance should have been 0.4mm, not 0.4

>>
>> 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."
>>
>>
>>
> 
> 


-- 
Hofstadter's Law:
"It always takes longer than you expect, even when you take into account
Hofstadter's Law."