M41ST84WMH ST Microelectronics, M41ST84WMH Datasheet - Page 14

• Manufacturer Part Number: M41ST84WMH
• Description: 5.0 or 3.0V / 512 bit 64 x 8 SERIAL RTC with SUPERVISORY FUNCTIONS
• Manufacturer: ST Microelectronics

M41ST84Y, M41ST84W
Data Retention Mode
With valid V
accessed as described above with READ or
WRITE cycles. Should the supply voltage decay,
the M41ST84Y/W will automatically deselect,
write protecting itself when V
V
by internally inhibiting access to the clock regis-
ters. At this time, the Reset pin (RST) is driven ac-
tive and will remain active until V
nominal levels. When V
Back-up Switchover Voltage (V
switched from the V
Figure 16. Power Down/Up Mode AC Waveforms
Table 8. Power Down/Up AC Characteristics
Note: 1. Valid for Ambient Operating Temperature: T
14/31
PFD
Symbol
t
t
REC(4)
t
t
DR
t
FB
t
PFD
2. V
3. V
4. Programmable (see Table 13, page 23)
5. At 25°C (when using SOH28 + M4T28-BR12SH SNAPHAT top); V
(max) and V
F
t
RB
(2)
R
(3)
(5)
V
PFD
PFD
PFD
(max) to V
(min).
(min) to V
CC
V
V
PFI to PFO Propagation Delay
V
V
Power up Deselect Time
Expected Data Retention Time
PFD
PFD
PFD
SS
applied, the M41ST84Y/W can be
V CC
V PFD (max)
V PFD (min)
V SO
INPUTS
RST
OUTPUTS
to V
(max) to V
(min) to V
(min) to V
PFD
SS
PFD
CC
fall time of less than t
PFD
(min) fall time of less than tF may result in deselection/write protection not occurring until 200µs after V
(min). This is accomplished
PFO
pin to the SNAPHAT
CC
(min) V
SS
PFD
(PER CONTROL INPUT)
PFD
falls below the Battery
V
VALID
(max) V
(min) V
RECOGNIZED
CC
CC
SO
CC
Parameter
tF
Fall Time
Rise Time
), power input is
falls between
CC
CC
CC
FB
may cause corruption of RAM data.
Fall Time
Rise Time
returns to
A
(1)
= –40 to 85°C; V
tFB
®
(or
tDR
DON'T CARE
CC
external) battery, and the clock registers and
SRAM are maintained from the attached battery
supply.
All outputs become high impedance. On power up,
when V
tion continues for t
mains active during this time (see Figure 16, page
14).
For a further more detailed review of lifetime calcu-
lations, please see Application Note AN1012.
HIGH-Z
= 2.7 to 3.6V or 4.5 to 5.5V (except where noted).
CC
= 0V.
tRB
CC
returns to a nominal value, write protec-
Min
300
10
10
40
10
1
tR
REC
Typ
(PER CONTROL INPUT)
15
. The RST signal also re-
tREC
RECOGNIZED
VALID
AI03681
Max
200
25
YEARS
CC
Unit
ms
µs
µs
µs
µs
µs
passes