Rainbow Electronics DS12C887 - Manual (Page 18)

DS12C887
18 of 19
POWER DOWN / POWER UP TIMING
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
CS at V
IH
before Power-
Down
t
PD
0 µ s
V
CC
slew from 4.5V to 0V
( CS at V
IH
)
t
F
4.0 ≤ V
CC
≤ 4.5V
300 µ s
V
CC
slew from 0V to 4.5V
( CS at V
IH
)
t
R
100 µ s
CS at V
IH
after Power-Up t
REC
20 200 ms
Expected Data Retention t
DR
10 years 10,11
(tA=25°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Expected Data Retention t
DR
10 years 10,11
Note:
The real time clock will keep time to an accuracy of ± 1 minute per month during data retention time for
the period of t
DR
.
Warning:
Under no circumstances are negative undershoots, of any amplitude, allowed when device is in battery
back-up mode.