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View Full Version : Schematic Sanity Check please...



__red__
02-21-2012, 11:15 PM
This is the most complex schematic and PCB that I have ever designed.

Could people please give it a sanity check? It's designed around the MAX7219.

Advice welcome.

Thanks,



Red

MacTuxLin
02-22-2012, 02:53 AM
If it is not a hassle, could you upload a .PDF or image instead? I don't have Diptrace installed.

Erik Friesen
02-22-2012, 12:36 PM
Its not the best idea to have ground plane islands, I see you have connected them with traces under the IC's. I would do it a little different. 30 mil tracks are larger than you need for driving leds.

tonyp12
02-23-2012, 01:40 AM
Is there a reson that so many traces have to cross path?, is it's becuase the item you connect have it so and can not be changed?

See how nice I made my triple 595 led board.
89853

__red__
02-23-2012, 02:26 AM
Is there a reson that so many traces have to cross path?, is it's becuase the item you connect have it so and can not be changed?

See how nice I made my triple 595 led board.
89853

That is nice. Wow.

Unfortunately I do need the connections to be in order so I do have to have crossings. Interestingly Erik above said that I didn't have to use such large traces so I guess I could have passed between the 0.1" pitch headers instead of being silly with vias.

__red__
02-23-2012, 04:56 AM
If it is not a hassle, could you upload a .PDF or image instead? I don't have Diptrace installed.

As requested...89916

__red__
02-23-2012, 04:58 AM
Its not the best idea to have ground plane islands, I see you have connected them with traces under the IC's. I would do it a little different. 30 mil tracks are larger than you need for driving leds.

So would you normally remove ground plane islands from your circuit or try and connect them via the top layer?

MacTuxLin
02-23-2012, 06:25 AM
As requested...89916I assume those caps are non-polarized...89918

__red__
02-23-2012, 07:43 AM
I assume those caps are non-polarized...89918

Yes.

My main concern is that this is the first time I've ever designed a schematic from a datasheet. The boards are ordered so they're set in stone (err, copper).

As a "fail-safe" I printed a "business card" on the back so if they all fail at least they'll have a second lease on life :-)

Erik Friesen
02-23-2012, 11:09 AM
It takes some careful routing to remove islands, sometimes you have to run some traces on the top side to allow a decent cross section.

Note the red circles, for example, those traces could be partially router to the top side to allow the ground plane to connect.