[sdiy] ICs close together in PCB layouts

[David G Dixon]

Dave, you should have no problems putting the ICs close together.  The
layout technique you're describing is exactly how I do mine, and I've never
experienced any problems.   However, you MUST leave one empty space between
14-pin DIPs because this package is actually just as long as the 16-pin
package -- they just leave extra plastic hanging over the ends of the last
pins -- so if you try to put two TL074s end to end without a gap, you might
actually have to sand off the ends (let's just say this was a lesson learnt
the hard way).

> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl 
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Dave Kendall
> Sent: Friday, March 30, 2012 1:56 PM
> To: synthdiy diy
> Subject: [sdiy] ICs close together in PCB layouts
> 
> 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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