Guide me through autorouting and component placement in PCB design

[mikee]

hi all
I am working on PCB design and i am at routing step..... i am using Protel 99se
I want to know following things:
I have read that in order to make PCB design successful it depends on 90% component placement and 10% autorouting....
1.How come i know which part should be at center and which components should be around it!
2. I want stepwise help for that!!!
3. I have placed components generally and then autoroute them.... It showed many violations!!! how could i be able to remove or edit those violations??
like for example if it is said that Capcitor13 net40 is violating a rule!!! how could i fix it!!

and many more about it!!! these and some more problems came when i autoroute my PCB final design.

I would like to have good guidance related to autorouting and component placement in PCB design...

 

[srizbf]

Re: Good guidance!!!

component placement generally is decided on the basis of frequency involved.
i mean for for HF you place the corresponding stage components together so that interference effects are minimised .

but in general , some pcb designers place all similar components together in one row and other simailar in other.

it is a long process for the new designers to get it routed in the first instant itself.

IMO if there is no other constraints ,
place the components in the same area as it is in original schematic. this way 'routing' problems are minimised .
arrange the components orientation in same format so that assembling is easier.


for the new designers this will give the result.

but all depends on the frequency as said earlier.

place all i/p and o/p in the periphery (another guideline only)