[sdiy] ICs close together in PCB layouts

[James Patchell]

It sounds like you are doing a good job, from the description.

Here is a picture of a board I did about 10 years ago (this is my volcal 
filter board).

http://www.noniandjim.com/Jim/synthmodules/vocalfilterpicture.html

You will note that it pretty much is done the same way you described, 
and this board worked quite well.  It has 3 state variable filters, 3 
diode function gens, a six input voltage controlled mixer.  Never had 
any problems with interaction.

-Jim

On 3/30/2012 1:55 PM, Dave Kendall wrote:
> Hi all.
>
> I've read a few times where people advise against butting up IC's 
> against each other when laying out a PCB. Obviously it depends on what 
> the ICs are, and what they're doing.......
>
> I'm currently perfboarding a design that's going to be quite dense in 
> ICs to fit it all on a reasonable sized board. So far the ±15V power 
> rails are being run up the middle between the legs of the ICs. The 
> first stage is a TL074, wired as a dual non-inverting summer per side 
> (±15V) . The next stage is a simple non-inverting voltage follower on 
> each side (±15V), followed by a comparator on each side (GND, +15V).
> Taps are being taken off to the side of the board at various points. 
> As the pins neatly line up OUT to IN (mostly) between the summers, 
> followers and comparators, is there any potential problem in having 
> the ICs close together?
> 100nF bypass caps will be added every 2nd IC or so.
>
> All signals are audio frequency, and either bipolar ±5V or GND to +15V 
> in the comparators. The chain then goes off to a bunch of logic ICs 
> running on GND/+15V.
>
> Any thoughts welcome.
>
> cheers,
> Dave
>
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