Circuit Design

I need someone to verify that my circuit design is correct, the schematic can be found at

http://www.rfsolutions.co.uk/products/radio_gsm_modems/Addlink.htm

Go to the AddLink 112 Integration manual, page 12

To see my design i will have to e-mail it to you as picture file.
StupotAsked:
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drelectroConnect With a Mentor Commented:
1/ It doesn't look like the RF module ground pins are connected (is this a 2 layer PCB ?)
2/ Ground traces are too thin, use a groundplane
3/ All parts should have the same size trace connecting each side (eg c1-4 are wrong) or else you'll get uneaven heating during reflow (manufacturing problems)
4/ Layout is generally poor (looks poorly autoroutered), may not pass EMC testing.

Other than that it looks like it matches the example in the integration manual .

What is the connector at the bottom right? Power ?

What were you planning to use as a power supply?
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luomCommented:
why not put the digram on the web?
and place a link from here,
try www.angelfire.com
but watch the spam
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StupotAuthor Commented:
I didn't know about that facility, anyway the pic is the background at :-

http://www.angelfire.com/electronic2/stuartjemson
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luomCommented:
Angelfire dosnt seam to like some thing on the web page,
the error is quoted bellow.

"The page you are attempting to access has been removed because it violated Angelfire's Terms of Service."

If this digram is complex, it might take a v.long time to verify!!
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StupotAuthor Commented:
ok, i've made another page, don't know why the last stopped working, but the new one works, or at least it did the last tme i checked!
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StupotAuthor Commented:
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StupotAuthor Commented:
Takes quite a while to load the page, but that's because of the size of the picture not the complexity of the diagram!  :)
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TheGafferCommented:
Nope, it has been binned again.

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StupotAuthor Commented:
ok how about i just send someone the picture, may be quicker!
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StupotAuthor Commented:
I've setup another website with a different provider, hopefully this one will work:-

http://2-minute-website.com/site/stuartjemson.trial/?r=1080511756

Let me know if this doesn't work!
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TheGafferCommented:
Sorry bud, to verify a schematic or design, we really need to see what components are there, not just the identifiers.
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StupotAuthor Commented:
Sorry, really didn't make it that clear.  If you turn the PCB picture 90 degrees clockwise, all the components will be alligned to the same position as the schematic in the integration manual.  The L's represent the inductors and the c's for capacitors.  The other components are the Max chip, serial port, power connector and the transceiver, which starts at pin 1 from the top left.
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StupotAuthor Commented:
P.S. Pin 1 of the transceiver starts from the top left after the rotation!
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StupotAuthor Commented:
It's a 4 layer board, the midlle two layers are used as a ground plane.  Also the capacitors C1 - C4 are on the main power line to the transceivers, so i thought i had to make the track wider?  I am not sure about the routing either, i was using Protel and once you've specified the connections the rest is supposedly done in the most efficient way.

In the bottom right it is a power connector and i was planning to simply use 4 AAA batteries for each transceiver, (Using NiMH batteries to give 4.8V).
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drelectroCommented:
I wouldn't bother with 4 layers it just adds to the expense, 2 would be fine and you could actually do it with 1 if you rotated the max chip 180 degrees
0603 parts would help too.
Checkout protel's Place Polygon feature to add the ground plane easily

Don't run seperate traces for ground just use via's to the ground plane like you've done on the RF xceiver.

Just use 1 set of 4 AAA power the MAX and the Radio (why use 2 sets?)

Which version of Protel are you using, I've been using it for about 16 years am currently using 98 and I've never liked the autorouter, it's certainly not efficient for small designs, it really has no idea about how to lay out a board correctly only how to make sure everything gets connected.


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StupotAuthor Commented:
Thanks for your help!  I shall make the changes, also what i meant by using 4 AAA batteries for each transceiver, was to use a set for each board at either end of the communication link.

Thanks again
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