AD5301: Reference usage

Document created by analog-archivist Employee on Feb 23, 2016
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Part Nr.: AD5301/5311/5321
I plan to use your DA converters on a board,
giving the possibility to my fab plant to select
any of the three refs mentionned above, depending
on components availability, as I only need 8 bit
My question is if there is a mean in *software* to
identify which ref is in use. I thought that
trying to write data to all one's and read back
could solve my problem, but the datasheet seems
to say that non significant bits are not defined.
The package I plan to use is the 8-lead µSOIC.


There is no way in software to determine which device has been placed. In fact
all parts in the series use the same 16 bit serial shift register to store the
power down bits and the data bits. For the parts with resolution less than
12bits, the unused bits are "don't cares" and are ignored by the DAC. If you
read back the 16 bit shift register, you will receive exactly what you wrote in
the last write cycle.

I would suggest that, since you only require 8 bit accuracy,  you do not know
which device has been placed. You can simply write two 8 bit data bytes with
zeros in the four LSBs, regardless of which device you are using.. In the  10
and 8bit parts, the lsbs will simply be ignored.