I need to use a ADMP401 microphone. How can I create the pcb hole, pad and paste mask for the microphone hole? I've attached a data sheet, reference page 6. Also I'm using v5.11.
I need to use a ADMP401 microphone. How can I create the pcb hole, pad and paste mask for the microphone hole? I've attached a data sheet, reference page 6. Also I'm using v5.11.
Dave,
I've have quite a few parts in my library so I'm not a complete novice I've also used Altium and Ultiboard in the past. I've gone ahead and made the footprint with just a hole for the mic, I figure I'll fake the ground around it on the pcb with polygons. But it would be nice to know if there is a way to make custom pads, especially surface mount in Eagle.
Thanks in advance for any help or advise you can give.'
Regards,
kj
Hi
In Eagle it is possible to create arbitrary pad shapes, and its easiest with SMD as you only need to create the top layer. Start with an SMD pad and then using lines/circles or polygons draw the required pad shape around the SMD pad.
Make sure that the SMD pad is at the dead centre of your polygon, and it will be recognised as part of the pad. Then when you come to the device creation you can connect pins to your new pads as normal.
Not a perfect situation I know, definitely needs upgrading. The only mention is buried deep in section 8:13 of the manual. It works though, and I have so far managed to make any SMD pad shape with it.
Dave,
I'll give it a try, thanks for the help
Regards,
kj
Due to the small size of the ADMP401 part you will run into issues with
the polygon approach.
This is due to the clearances from holes and signals the DRC will use.
Holes keep the flood fills away from the hole and the polygon.
A further consideration is the need to keep solder out of the microphone
hole so I rejected using a pad which is drilled out further with a HOLE
later as this brings copper to the hole edge and there is no way to prevent
the solder stop mask.
I was interested in the challenge this scale of device would provide and I
settled as per the attached library.
You will get DRC errors to approve.
Within a flood fill, for the pad 3 ring around the hole you will need to
fake the thermals.
Hope this is of help
Warren
--
Web access to CadSoft support forums at www.eaglecentral.ca. Where the CadSoft EAGLE community meets.
Hi everyone,
I think this post is relevant to my problem as I too have an analog MEMS microphone (SMD device) which has a similar footprint. The part is Knowles Acoustics SPU0410LR5H-QB. Please go through the specifications and let me know if anyone can help me with creating a library part for this SMD part. I am relatively new to this. Thanks a lot.
Akanksha
An excellent for beginner or expert alike is https://learn.sparkfun.com/tutorials/designing-pcbs-smd-footprints
Give it a read and you should be able to do a great design.
Clem