Grounding Q's

[meta]

Hi...

When doing the layout for the gnd on a dac brd I've seen/read it's best to split the A and D gnds and join them under the dac/adc chip itself. But there is only one ground right? I mean on the psu itself the grounds are joined there so why split em again on the dac brd only to join them once again? Or with these split gnd designs is there a specifc psu design thats needed too?

Cheers

[Fin]

You are about to open a can of worms.

Questions re: digital grounding

Optimum Decoupling of Digital ICs

[Jocko Homo]

Guido does not like it.

It could be made to work, but the rationale for doing it seems flawed at times.

Making one for the analog section of the CDP...you know.......the op-amps that make up the I/V stage ,etc......there might be some justification for it.

But as for the DAC......I would use one for it and all the other digital stuff.

(Yeah.....I know......someone will point out that I have used 2 in the past. As well as one.........I try most everything once. Sometimes more than once.)

BTW.......the reason that separate ground pins for analog and digital in a DAC came about was to reduce the inductance, making each one "closer" to ground.

Jocko

Jocko

[Oli]

I 'opened' the second can of worms- the second link highlighted.

I was on a quest to find the ideal grounding arrangement. Eventually I opted for the single ground plane arrangement. There is more to it than just that and you will need to read the link for details. I felt that there was sufficient scientific justification for a single ground plane and I loved the simplicity it offered for design. I am still fine tuning the PCB, although components have been purchased. The proof of the pudding will be in the eating (or the listening in this case) I will post on my thread when I have further experience.

[meta]

Thanks - def gonna be some further head scratchin n chin rubbin to be dun