pls guide me for mixsignal pcb layout

[jpbhatt]

hello all respected members

i m from delhi(india)

pls any one will guide me that what strategy is used for placing components for mixed signal pcb layouts bcz till now i had not design such types of layout . and what precautions must take during layout designing.

thanks all respected members.

any one can help me at jpladdi@yahoo.co.in

 

[dmd4raj]

first split the analog and Digital High speed devices based on their Reference.

Then Split the ground plane as analog and digital and place the components with respect to its reference.
while routing the analog and digital donot cross the split ground planes.route with respect to its reference ground plance

Donot let the grounds as such.connect the two grounds at any one point either at device or else power source with ferrite bead (to suppress high freq., nosie pulses) ,2 different ground in a system makes it as dipole antenna and radiates the signals


Regards
RAJAN.K

 

[jpbhatt]

dear rajan

thanks to u bcz u have given me a lot knowledge through ur data.

thanks one again and best regard

god bless u.

 

[yassin.kraouch]

really thank you very very very much

 

[TA37]

I just came across https://www.ultracad.com/article_outline.htm series of articles, which is a good source. You're probably going to want to read https://www.ultracad.com/articles/planesplits.pdf at least.

As the other posters said, keep analog and digital sections separate. I've never gone so far as to use a ferrite on the GND plane, just power, but instead just split the gnd planes and have them join at ONE point, an isthmus, as close as possible to where power enters the analog section/room. This is so the return current doesn't make a big loop (possibly through the digital side.) Either thru a jumper, or just use one GND plane but then use a line to almost cut it in two, with the join directly underneath the power ferrite+cap filter.

The GND split should go directly underneath any mixed signal ICs, like ADCs. So that the analog pins are on the analog side of GND and vice-versa. Make sure to read the datasheet about which GND pins are analog GND and which are digital GND. Make sure bypass caps are tied to the correct GND, too.

the GND split and power plane splits should line up. if they are staggered, you will get capacitance between analog GND and digital power, or digital GNDto analog power.

....ok, just got done typing that, then looked at dmd4raj's pdf files and lots of it is in there, better than I can describe it.

 

[jpbhatt]

THAKS TA37 IT REALLY HELP ME.

THANKS AGAIN