AVR-Chat

On Wed, Aug 12, 2009 at 12:56 PM, Roland
Jollivet<Roland.Jollivet@gmail.com> wrote:
> Clamping to the Vcc rail in this app might not be a good idea. If the
> current draw of the entire cct is low, and the Ain voltage goes too high,
> it'll just pull the rail voltage up too. So then you need a Zener on the Vcc
> rail. So just use one on the a/d in, instead.

Linear regs can have interesting behaviour if VCC rises above the
regulator voltage, especially if VCC keeps bouncing around.

Definitely a can of worms that is better left under the sink.