m41t93 STMicroelectronics, m41t93 Datasheet - Page 15

• Manufacturer Part Number: m41t93
• Description: Serial Spi Bus Rtc With Battery Switchover
• Manufacturer: STMicroelectronics

2.3
2.4
Note:
Data retention and battery switch-over (V
Once V
switches over to the battery and powers down into an ultra low current mode of operation to
preserve battery life. If V
from V
clock registers and user RAM will be maintained by the attached battery supply.
When it is powered back up, the device switches back from battery to V
hysteresis. When V
on Battery Storage Life refer to Application Note AN1012.
Power-on reset (t
The M41T93 continuously monitors V
the RST output pulls low (open drain) and remains low after power-up for t
typical) after V
The t
below V
RST output is affected by the t
The RST pin is an open drain output and an appropriate pull-up resistor to V
chosen to control the rise time.
rec
CC
CC
RST
period does not affect the RTC operation. Write protect only occurs when V
to V
falls below the switchover voltage (V
. When V
BAT
CC
rises above V
when V
CC
CC
rises above V
BAT
rises above V
CC
rec
is less than, or greater than V
drops below V
)
rec
RST
period.
(max).
CC
RST
RST
. When V
, it will recognize the inputs. For more information
, the RTC will be selectable immediately. Only the
RST
SO
(see
CC
= V
Figure 18 on page
falls to the power fail detect trip point,
RST
), the device automatically
RST
, the device power is switched
SO
= V
RST
CC
40). At this time the
rec
at V
)
CC
(210ms
SO
should be
+
CC
15/51
is