DS1245Y/AB
POWER-DOWN/POWER-UP TIMING
PARAMETER
CE
,
WE
(t
A
: See Note 10)
MIN
0
300
300
2
125
TYP
MAX
UNITS
µs
µs
µs
ms
NOTES
11
at V
IH
before Power-Down
SYMBOL
t
PD
t
F
t
R
t
REC
V
CC
slew from V
TP
to 0V (
CE
at V
IH
)
V
CC
slew from 0V to V
TP
(
CE
at V
IH
)
CE
,
WE
at V
IH
after Power-Up
(t
A
=25°C)
PARAMETER
Expected Data Retention Time
SYMBOL
t
DR
MIN
10
TYP
MAX
UNITS
years
NOTES
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
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
DH
, t
DS
are 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 latter than the
WE
low transition, the output
buffers remain in a high impedance state during this period.
7. If the
CE
high transition occurs prior to or simultaneously with the
WE
high transition, the output
buffers remain in high impedance state during this period.
8. If
WE
is low or the
WE
low transition occurs prior to or simultaneously with the
CE
low transition,
the output buffers remain in a high impedance state during this period.
9. Each DS1245 has a built-in switch that disconnects the lithium source until V
CC
is first applied by the
user. The expected t
DR
is defined as accumulative time in the absence of V
CC
starting from the time
power is first applied by the user.
10. All AC and DC electrical characteristics are valid over the full operating temperature range. For
commercial products, this range is 0°C to 70°C. For industrial products (IND), this range is -40°C to
+85°C.
11. In a power-down condition the voltage on any pin may not exceed the voltage on V
CC
.
12. t
WR1
and t
DH1
are measured from
WE
going high.
13. t
WR2
and t
DH2
are measured from
CE
going high.
14. DS1245 DIP modules are recognized by Underwriters Laboratory (U.L.) under file E99151.
DS1245 PowerCap modules are pending U.L. review. Contact the factory for status.
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DALLAS [ DALLAS SEMICONDUCTOR ]
