in the Rev 0. of the AD5259 datasheet there is a table showing the possibility
to address 9 devices.
On stage is called "NC"
meaning I have A0 and A1
and the ligic Levels "1", "0" and "NC"
this allows to address 9 parts.
Where is this gone?
Analog Devices removed the "NC" option moving from datasheet Rev 0 to Rev A.
The part includes a current detector in these pins for the floating condition
This circuit somehow is quite sensitive and it could fail under some
(In fact, some of the new digipots include this circuit but a malfunction is
detected at low voltage (<2.6V) and low temperature)
In order to avoid customer problems, these options were deleted from the DS.
The circuit is still inside the circuit so if you never experience problems
using these address (NC), he/she can continue using it but as these address are
not in the DS we cannot assume any responsibility and we are not able to
guarantee to function under all circumstances.
the normal way is:
The A0 and A1 are two state the Logic levels are specified
DIGITAL INPUTS AND OUTPUTS
Input Logic High VIH 0.7 × VL VL + 0.5 V
Input Logic Low VIL ?0.5 0.3 × VL V
With A0 and A1 - 4 parts are addressable by logic.