Datasheet

AD7834/AD7835
Rev. D | Page 19 of 28
POWER-ON OF THE AD7834/AD7835
V
REF
(+)
V
REF
(–)
AD7834
1
SD103C
1N5711
1N5712
1
ADDITIONAL PINS OMITTED FOR CLARITY
01006-025
Power is normally applied to the AD7834/AD7835 in the
following sequence: first V
DD
and V
SS
, then V
CC
, and then
V
REF
(+) and V
REF
(−). The V
REF
pins are not allowed to float when
power is applied to the part. V
REF
(+) is not allowed to go below
V
REF
(−) − 0.3 V. V
REF
(−) is not allowed to go below V
SS
− 0.3 V.
V
DD
is not allowed to go below V
CC
− 0.3 V.
Figure 25. Power-On Protection
In some systems, it is necessary to introduce one or more
Schottky diodes between pins to prevent the above situations
arising at power-on. These diodes are shown in
Figure 25.
However, in most systems, with careful consideration given to
power supply sequencing, the above rules are adhered to, and
protection diodes are not necessary.