[sdiy] So what's the difference between these IC's?

[Paul Schreiber]

> And the same applies to the CD4016 versus the CD4066 they're both quad
> bilateral switches.  So - what's the difference, if any?

Switch 'On' resistance, the 4066 is lower (something on the order of 300 ohms
for a 4016 and 120 ohms for a 4066). Maxim and Vishay (former Siliconix) make
switches down to 1 ohm. The other thing is 'flatness' of the resistance versus
power supply voltage. The DG4xx series of switches are pretty nice. And if you
want to get *really* technical, for sample/holds you have to worry about "charge
injection" which is like DC offset in an op amp.

Paul S.