参数资料
型号: M48T248V-85PM1TR
厂商: 意法半导体
英文描述: 5.0 or 3.3V, 1024K TIMEKEEPER SRAM with PHANTOM
中文描述: 5.0或3.3V,1024K与幻象计时器的SRAM
文件页数: 14/24页
文件大小: 306K
代理商: M48T248V-85PM1TR
M48T248Y, M48T248V
14/24
Data Retention Mode
Data can be read or written only when V
CC
is
greater than V
PFD
. When V
CC
is below V
PFD
(the
point at which write protection occurs), the clock
registers and the SRAM are blocked from any ac-
cess. When V
CC
falls below the Battery Switch
Over threshold (V
SO
), the device is switched from
V
CC
to battery backup (V
BAT
). RTC operation and
SRAM data are maintained via battery backup un-
til power is stable. All control, data, and address
signals must be powered down when V
CC
is pow-
ered down.
The lithium power source is designed to provide
power for RTC activity as well as RTC and RAM
data retention when V
CC
is absent or unstable.
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
CC
. Each unit is shipped with its energy source
disconnected, guaranteeing full energy capacity.
When V
CC
is first applied at a level greater than
V
PFD
, the energy source is enabled for battery
backup operation. The actual life expectancy will
be much longer if no battery energy is used (e.g.,
when V
CC
is present).
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
A
= 0 to 70°C; V
CC
= 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
2. At 25°C, V
CC
= 0V; the expected t
DR
is defined as cumulative time in the absence of V
CC
with the clock oscillator running.
Symbol
Parameter
(1)
Min
Max
Unit
t
REC
V
PFD
(max) to CE low
1.5
2.5
ms
t
F
V
PFD
(max) to V
PFD
(min) V
CC
Fall Time
300
μ
s
t
FB
V
PFD
(min) to V
SO
V
CC
Fall Time
10
μ
s
t
R
V
PFD
(min) to V
PFD
(max) V
CC
Rise Time
0
μ
s
t
PD
CE High to Power-Fail
0
μ
s
t
DR(2)
Expected Data Retention Time
10
Years
tDR
tF
tREC
tR
tPD
tFB
VSO
VCC
CE
VPFD (max)
VPFD (min)
AI04236
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M48T248Y-70PM1TR 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5.0 or 3.3V, 1024K TIMEKEEPER SRAM with PHANTOM
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