dacs, microcontrollers and ground planes

[Ken Smith]

Well, it's hard to quantify. I like source termination for other
reasons, so it's pleasing to think that it improves analog s/n too.

It doesn't hurt anything. Also if the ground's impedance in not low
enough or the bypasses not big enough, the effect of a current spike in
the past can still be hanging around.

I've definitely seen serious data-bus-line noise induced into SAR
adc's, cured by adding gated buffers in the data lines. And DAC
feedthrough is the nemesis of my otherwise-perfect life.

As have I. I've used the HC373 or HC374 to latch and drive the bus. The
advantage of the latch is that it can hold the bus while the ADC does the
next convert.