Datasheet

AD5171
Rev. D | Page 15 of 24
TERMINAL VOLTAGE OPERATING RANGE POWER-UP/POWER-DOWN SEQUENCES
There are also ESD protection diodes between V
DD
and the
RDAC terminals; therefore, the V
DD
of the AD5171 defines their
voltage boundary conditions (see Figure 31). Supply signals
present on Terminal A, Terminal B, and Terminal W that
exceed V
DD
are clamped by the internal forward-biased diodes
and should be avoided.
Similarly, because of the ESD protection diodes, it is important
to power V
DD
first before applying any voltages to Terminal A,
Terminal B, and Termina l W. Other wise, t he dio de i s for ward-
biased such that V
DD
is powered unintentionally and can affect
the remainder of the users’ circuits. The ideal power-up sequence is
the following order: GND, V
DD
, digital inputs, and V
A
/V
B
/V
W
.
The order of powering V
A
, V
B
, V
W
, and the digital inputs is not
important as long as they are powered after V
DD
. Similarly, V
DD
should be powered down last.
GND
A
W
B
V
DD
03437-029
Figure 31. Maximum Terminal Voltages Set by V
DD