DS12B887 Datasheet, PDF (15/16 Pages) Dallas Semiconductor – Real Time Clock

POWER DOWN/POWER UP TIMING
V_CC
4.50V
DS12B887
3.2V
t_F
t_PD
t_R
t_REC
CS
CURRENT SUPPLIED
FROM INTERNAL
LITHIUM ENERGY CELL
DATA RETENTION
t_DR
POWER DOWN/POWER UP TIMING
PARAMETER
SYMBOL MIN
TYP
MAX
UNITS NOTES
CS at V_IH before Power-Down
t_PD
0
ms
V_CC slew from 4.5V to 0V
t_F
300
ms
(CS at V_IH)
V_CC slew from 0V to 4.5V
t_R
100
ms
(CS at V_IH)
CS at V_IH after Power-Up
t_REC
20
200
ms
(t_A = 25°C)
PARAMETER
Expected Data Retention
SYMBOL MIN
t_DR
10
TYP
MAX
UNITS
years
NOTES
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 backup
mode.
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