User Manual

DS1220AB/AD
100495 7/10
8
POWER-DOWN/POWER-UP CONDITION
3.2V
DATA RETENTION TIME
V
CC
t
F
t
PD
t
R
t
REC
CE
t
DR
LEAKAGE CURRENT
I
L
SUPPLIED FROM
LITHIUM CELL
V
TP
POWER-DOWN/POWER-UP TIMING (t
A:
See Note 10)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
CE at V
IH
before Power-Down t
PD
0 µs 11
V
CC
slew from V
TP
to 0V (CE at
V
IH
)
t
F
300 µs
V
CC
slew from 0V to V
TP
(CE at
V
IH
)
t
R
300 µs
CE at V
IH
after Power-Up t
REC
2 125 ms
(t
A
=25°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Expected Data Retention Time t
DR
10 years 9
WARNING:
Under no circumstances are negative undershoots, of any amplitude, allowed when device is in the battery backup
mode.
NOTES:
1. WE is high for a read cycle.
2. OE
= V
IH
or V
IL
. If OE = V
IH
during write cycle, the output buffers remain in a high impedance state.
3. t
WP
is specified as the logical AND of CE and WE. t
WP
is measured from the latter of CE or WE going low to
the earlier of CE or WE going high.
4. t
DS
is measured from the earlier of CE or WE going high.
5. These parameters are sampled with a 5 pF load and are not 100% tested.
6. If the CE
low transition occurs simultaneously with or later than the WE low transition, the output buffers re-
main in a high impedance state during this period.