Clock operation M41T66
22/34 Doc ID 15108 Rev 2
3.9 Initial power-on defaults
Upon application of power to the device, the register bits will initially power-on in the state
indicated in Ta bl e 5 .
Table 5. Initial power-on default values
Condition ST OF OFIE OUT AFE SQWE RS3-1 RS0 Watchdog
Initial power-up
(1)
1. All other control bits power-up in an undetermined state.
01 0 1 0 1 0 1 0
Table 6. Century bits examples
CB0 CB1 Leap year? Example
(1)
1. Leap year occurs every four years (for years evenly divisible by four), except for years evenly divisible by
100. The only exceptions are those years evenly divisible by 400 (the year 2000 was a leap year, year
2100 is not).
00Yes2000
0 1 No 2100
1 0 No 2200
1 1 No 2300
M41T66 Maximum ratings
Doc ID 15108 Rev 2 23/34
4 Maximum ratings
Stressing the device above the rating listed in the absolute maximum ratings table may
cause permanent damage to the device. These are stress ratings only and operation of the
device at these or any other conditions above those indicated in the operating sections of
this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Table 7. Absolute maximum ratings
Sym Parameter Conditions
(1)
1. Test conforms to JEDEC standard.
Value
(2)
2. Data based on characterization results, not tested in production.
Unit
T
STG
Storage temperature (V
CC
off, oscillator off) –55 to 125 °C
V
CC
Supply voltage –0.3 to 5.0 V
T
SLD
(3)
3. Reflow at peak temperature of 260 °C (total thermal budget not to exceed 245 °C for greater than 30
seconds).
Lead solder temperature for 10 seconds 260 °C
V
IO
Input or output voltages –0.2 to V
CC
+0.3 V
I
O
Output current 20 mA
P
D
Power dissipation 1 W
V
ESD(HBM)
Electro-static discharge voltage
(human body model)
T
A
= 25 °C >1500 V
V
ESD(RCDM)
Electro-static discharge voltage
(robotic charged device model)
T
A
= 25 °C >1000 V
DC and AC parameters M41T66
24/34 Doc ID 15108 Rev 2
5 DC and AC parameters
This section summarizes the operating and measurement conditions, as well as the DC and
AC characteristics of the device. The parameters in the following DC and AC Characteristic
tables are derived from tests performed under the measurement conditions listed in the
relevant tables. Designers should check that the operating conditions in their projects match
the measurement conditions when using the quoted parameters.
Figure 14. AC measurement I/O waveform
Figure 15. Crystal isolation example
1. Substrate pad should be tied to V
SS
.
2. To avoid coupling between pin 4 (SQW) and pin 2 (XO), pin 3 (GND) should be routed adjacent to pin 4 for
isolation purposes.
Table 8. Operating and AC measurement conditions
(1)
1. Output Hi-Z is defined as the point where data is no longer driven.
Parameter M41T66
Supply voltage (V
CC
) 1.5 V to 4.4 V
Ambient operating temperature (T
A
) –40 to 85 °C
Load capacitance (C
L
) 50 pF
Input rise and fall times 5 ns
Input pulse voltages 0.2 V
CC
to 0.8 V
CC
Input and output timing ref. voltages 0.3 V
CC
to 0.7 V
CC
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M41T66Q6F

Mfr. #:
Manufacturer:
STMicroelectronics
Description:
Real Time Clock real-time clock with alarms
Lifecycle:
New from this manufacturer.
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