M41T83SQA6F STMicroelectronics, M41T83SQA6F Datasheet - Page 39

• Manufacturer Part Number: M41T83SQA6F
• Description: IC RTC SERIAL W/BATT SW 16QFN
• Manufacturer: STMicroelectronics
• Type: Clock/Calendar/Alarmr

Specifications of M41T83SQA6F

• Memory Size: 32B
• Time Format: HH:MM:SS:hh (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-QFN
• Clock Format: 12Hr / 24Hr
• Clock Ic Type: RTC
• Interface Type: I2C, Serial
• Supply Voltage Range: 3V To 5.5V
• Digital Ic Case Style: QFN
• No. Of Pins: 16
• Rohs Compliant: Yes
• For Use With: 497-10833 - DAUGHTER-CARD M41T83SQA6E QFN16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6887-2; M41T83SQA6F

M41T82-M41T83
3.10
Battery low warning
The M41T8x automatically checks the battery each time V
clock rolls over at midnight.
V
register 0Fh, is set if the battery voltage is found to be less than V
greater than V
The BL bit retains its state until the next battery check occurs. This means the BL bit will not
clear immediately upon battery replacement, but only after the next battery check occurs at
the next power-up or midnight rollover.
If a battery low is generated during a power-up sequence, this indicates that the battery is
below approximately 2.5 volts and may not be able to maintain data integrity. Clock data
should be considered suspect and verified as correct. A fresh battery should be installed.
If a battery low indication is generated during the 24-hour interval check, this indicates that
the battery is near end of life. However, data is not compromised due to the fact that a
nominal V
battery backup mode, the battery should be replaced.
Midnight rollover check
As shown in
battery, then compares V
present, an open condition on the V
is performed, the RTC removes the load.
Power-up battery check
During the power-up check, no load is applied to the battery under the assumption the
battery has already been stressed to its working level by having powered the RTC in backup
mode. If no battery is present, V
indeterminate.
Figure 22. Battery check
BAT
is compared to V
CC
V
BAT
Figure
is supplied. In order to ensure data integrity during subsequent periods of
BL
, the BL bit is cleared during battery check.
22, during the midnight rollover check, the M41T8x applies a load to the
BL
R
L
BAT
(approximately 2.5 V), then the battery low (BL) bit, D4 of flags
Only at
rollover
to V
Doc ID 12578 Rev 12
BAT
BL
BAT
and updates the BL bit accordingly. Because a load is
will be floating and the battery check result will be
At power-up
and at rollover
pin will result in the BL bit being set. After the check
V
BL
=2.5V
CC
powers up and each time the
BL
. Similarly, if V
FF
S
R
Clock operation
Q
BL
BAT
AM03009v1
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is