also for audio.
Use what you prefer - in very most amps noise is dominated anyway by other factors, like magnetic induction, wiring, grounding, ripple...
@swordfishy: depends on your grounding scheme ;-) Usually one defines separate signal and power grounds. Alternatively, pour a ground plane that does not cover power devices and connect it to signal ground. The power parts get their own ground (or go balanced and forget about this issue).
As that's a chipamp, I think you shouldn't have problems connecting a full plane to signal ground. I wouldn't reference signal input to power ground.
Have fun, Hannes
@swordfishy: depends on your grounding scheme ;-) Usually one defines separate signal and power grounds. Alternatively, pour a ground plane that does not cover power devices and connect it to signal ground. The power parts get their own ground (or go balanced and forget about this issue).
As that's a chipamp, I think you shouldn't have problems connecting a full plane to signal ground. I wouldn't reference signal input to power ground.
Have fun, Hannes
looks like you have given me quite a bit of homework to complete, before I can offer any further advice.
There's not much magic about ground planes vs. star grounding.
One trades low impedance against capacitance to ground, that's it. The higher the frequencies to be transmitted, the more important are reactive components of the ground impedance. Consequently, for analog Mhz signals the shortest path is (often) not the path of lowest impedance.
A solid ground plane increases capacitive coupling to ground by some pf/cm^2, which forms a low pass filter. That's usually not a big deal, though. There are hatched variants of ground planes, but these again trade lower coupling for higher impedance.
Most DIY pcbs are double-sided as that's widely available. Most designs need already both sides for proper routing, so an additional ground plane is usually largely compromised with large holes.
In my view, a ground plane comes handy for high speed (MHz) signals or multilayer designs (beyond 2 layers).
For audio, star ground gave me always excellent results.
Have fun, Hannes
For more details, I refer to dozens of application notes that are freely available, among:
Linear AN47
Analog AN-202
Circuit layout techniques and tips 1-6, Bonnie Baker, Microchip
We have numerous design that use various chip amps for both audio and instrumentation purposes, though mostly SMD, due to space constraints and complexity we use one contigous ground plane, no splits etc. We have never had any problems. If I was using through hole I would probably isolate the high current area's, but would still use a ground plane with possibly stragecic slots to isolate the high current paths, or totaly isolate these using flying leads (this technique is used in motor control where the PCB just will not carry the currents). But as a preference a solid ground is prefferable, especially when trying to get things passed for EMC.
There is a similar discussion here with some interesting links:
Analog and Digital Ground Planes - PCB Matrix Forum
Generaly when designing consumer products price plays a big big part, hence double sided boards are often used. I belive this will change as more stringent EMC requirements and availability of cheeper multilayer PCBs' from China will make multilayer PCB more prevelant in consumer goods. Some top end manufacturers all ready use the fact that they use multilayer as a marketing point.
But as said earlier we have not seen any degrading of signals etc by nusing a solid contigous ground.
There is a similar discussion here with some interesting links:
Analog and Digital Ground Planes - PCB Matrix Forum
Generaly when designing consumer products price plays a big big part, hence double sided boards are often used. I belive this will change as more stringent EMC requirements and availability of cheeper multilayer PCBs' from China will make multilayer PCB more prevelant in consumer goods. Some top end manufacturers all ready use the fact that they use multilayer as a marketing point.
But as said earlier we have not seen any degrading of signals etc by nusing a solid contigous ground.
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