| The Use of back-to-back Schottky diodes,
between the analog and digital grounds, is to catch any excessive differential
shifts in ground potential--steady-state or fast events. This can happen
when the distances from the device to the power supply (where the two grounds
are reconciled) is excessive. Depending on the XL and Zo
of
the traces, the system clock's rise and fall times; and the currents involved:
the distance or trace lengths, do not have to be very long to cause mischief. |
