m41t315v STMicroelectronics, m41t315v Datasheet - Page 11

• Manufacturer Part Number: m41t315v
• Description: Serial Access Phantom Rtc Supervisor
• Manufacturer: STMicroelectronics

Table 2.
1. See
2.1
Figure 6.
Deselect
WRITE
READ
READ
Deselect
Deselect
Mode
Table 11 on page 21
WE
CEI
OE
Q
Operating modes
Non-volatile supervisor operation
A switch is provided to direct power from the battery input or V
voltage drop of 0.3 Volts. The V
CMOS SRAM. The M41T315Y/V/W safeguards the clock and RAM data by power-fail
detection and write protection.
Power-fail detection occurs when V
reference. The M41T315Y/V/W constantly monitors the V
than V
for external RAM write protection. During nominal supply conditions, CEO will track CEI with
a propagation delay. Internally, the M41T315Y/V/W aborts any data transfer in progress
without changing any of the device registers and prevents future access until V
V
Read mode waveforms
PFD
V
SO
.
4.5 to 5.5V
3.0 to 3.6V
2.7 to 3.3V
to V
Figure 5 on page 9
PFD
≤ V
V
PFD
, power-fail circuitry forces the chip enable output (CEO) to V
or
or
SO
CC
for details.
tCOE
(1)
(min)
(1)
tCO
tOEE
CEI
illustrates a typical RAM/clock interface.
V
V
V
V
X
X
IH
IL
IL
IL
tCW
tOW
tOE
CCO
OE
V
V
CCI
X
X
X
X
output pin is used to supply uninterrupted power to
IH
IL
DATA OUTPUT VALID
falls below V
tRC
WE
V
V
V
X
X
X
IH
IH
IL
PFD
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
D
tODO
tRR
D
tOD
IN
which is set by an internal bandgap
CCI
D
supply pin. When V
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
CCI
OUT
Q
to V
Battery back-up mode
CCO
CCI
CMOS standby
with a maximum
or V
AI04259
Standby
Power
Active
Active
Active
CCI
BAT
CCI
-0.2 volts
exceeds
is less
11/30