Rainbow Electronics DS1258Y_AB - Manual (Page 7)

DS1258Y/AB
100395 7/9
POWER-DOWN/POWER-UP CONDITION
V CC
3.2V
t F
t PD
t R
t REC
DATA RETENTION
TIME
t DR
LEAKAGE CURRENT
I
L SUPPLIED FROM
LITHIUM CELL
WE, CEU, CEL
DS1230Y 4.50V
DS1230AB 4.75V
SEE NOTE 11
POWER-DOWN/POWER-UP TIMING (t
A
: See Note 10)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
CEU, CEL, WE at V
IH
before
Power-Down
t
PD
0
m s 11
V
CC
Slew from V
TP
to 0V t
F
300
m s
V
CC
Slew from 0V to V
TP
t
R
300
m s
CEU, CEL or 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 circumstance are negative undershoots, of any amplitude, allowed when device is in 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 CEU or CEL and WE. t
WP
is measured from the latter of CEU, CEL or
WE going low to the earlier of CEU, CEL or WE going high.