M48T248V ST Microelectronics, M48T248V Datasheet - Page 14

• Manufacturer Part Number: M48T248V
• Description: 5.0 or 3.3V / 1024K TIMEKEEPER SRAM with PHANTOM
• Manufacturer: ST Microelectronics

M48T248Y, M48T248V
Data Retention Mode
Data can be read or written only when V
greater than V
point at which write protection occurs), the clock
registers and the SRAM are blocked from any ac-
cess. When V
Over threshold (V
V
SRAM data are maintained via battery backup un-
til power is stable. All control, data, and address
signals must be powered down when V
ered down.
The lithium power source is designed to provide
power for RTC activity as well as RTC and RAM
Figure 9. Power Down/Up Mode AC Waveforms
Table 9. Power Down/Up Trip Points DC Characteristics
Note: 1. Valid for Ambient Operating Temperature: T
14/24
CC
to battery backup (V
2. At 25°C, V
Symbol
CE
t
V CC
t
DR
REC
t
t
t
PD
t
FB
R
F
(2)
V PFD (max)
V PFD (min)
PFD
CC
CC
V SO
= 0V; the expected t
SO
. When V
falls below the Battery Switch
V
V
V
V
CE High to Power-Fail
Expected Data Retention Time
), the device is switched from
PFD
PFD
PFD
PFD
(max) to CE low
(max) to V
(min) to V
(min) to V
BAT
tPD
CC
). RTC operation and
is below V
DR
SO
PFD
PFD
is defined as cumulative time in the absence of V
Parameter
V
(max) V
CC
(min) V
CC
A
Fall Time
tFB
PFD
= 0 to 70°C; V
tF
is pow-
CC
CC
CC
(1)
(the
Fall Time
Rise Time
is
CC
tDR
data retention when V
The capability of this source is sufficient to power
the device continuously for the life of the equip-
ment into which it has been installed. For specifi-
cation purposes, life expectancy is ten (10) years
at 25°C with the internal oscillator running without
V
disconnected, guaranteeing full energy capacity.
When V
V
backup operation. The actual life expectancy will
be much longer if no battery energy is used (e.g.,
when V
= 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
CC
PFD
. Each unit is shipped with its energy source
, the energy source is enabled for battery
CC
CC
is present).
is first applied at a level greater than
Min
300
1.5
10
10
0
0
CC
with the clock oscillator running.
CC
tREC
is absent or unstable.
Max
2.5
tR
AI04236
Years
Unit
ms
s
s
s
s