Remember small signal analysis? Power rails are both ground. What do you
think the impedance of the power supply decoupling cap is at 4 MHz?



At 11:52 AM 6/12/99 -0500, you wrote:
>> Whoops, I didn't check the specs before I blurted that out. I mean the
>> positive supply pin. Its also an AC ground, which is all the osc caps care
>> about.
>
>
>The positive supply pin (vcc) is NOT an AC ground, unless external
>components make it so. If you've got space for the externals, then you can
>just as well return the osc caps to the chip ground (vss). Returning them to
>VSS through any component (which will have a finite, non-zero impedance)
>will always be worse than returning them to VSS directly.
>
>