IC SNAPHAT BATT/CRYSTAL 28-SOIC

M4T32-BR12SH1

Manufacturer Part NumberM4T32-BR12SH1
DescriptionIC SNAPHAT BATT/CRYSTAL 28-SOIC
ManufacturerSTMicroelectronics
M4T32-BR12SH1 datasheets
MSDS Material Safety Datasheet
 

Specifications of M4T32-BR12SH1

Battery TypeLi-(CF)Operating Supply Voltage0 V to 2.8 V
Maximum Operating Temperature+ 70 CMinimum Operating Temperature0 C
Package / CaseSOIC-28Mounting StyleSMD/SMT
Capacity120 mAhChemical SystemLithium Poly-Carbonmonoflouride
Primary TypePackSizeCylindrical
StandardsUL RecognizedTemperature, Operating0 to +75 °C
Temperature, Operating, Maximum70 °CTemperature, Operating, Minimum0 °C
TerminationSnap-OnVoltage, Battery3 V
Voltage, Rating3 VSupply Voltage Range2.8V
Battery Ic Case StyleSOICNo. Of Pins4
Operating Temperature Range0°C To +70°CCrystal TerminalsSnap On
Load Capacitance12.5pFRohs CompliantYes
Crystal Mounting TypeSMDLead Free Status / RoHS StatusLead free / RoHS Compliant
Other names497-3687-5  
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Clock operations
Table 5.
Register map
Address
D7
7FFFh
7FFEh
0
7FFDh
0
7FFCh
0
7FFBh
0
7FFAh
0
7FF9h
ST
7FF8h
W
Keys:
S = SIGN bit
FT = FREQUENCY TEST bit (must be set to '0' upon power for normal operation)
R = READ bit
W = WRITE bit
ST = STOP bit
0 = Must be set to '0'
CEB = CENTURY ENABLE bit
CB = CENTURY bit
Note:
When CEB is set to '1,' CB will toggle from '0' to '1' or from '1' to '0' at the turn of the century
(dependent upon the initial value set).
When CEB is set to '0,' CB will not toggle. The WRITE bit does not need to be set to write to
CEB.
3.4
Calibrating the clock
The M48T35AV is driven by a quartz-controlled oscillator with a nominal frequency of
32,768 Hz. The devices are tested not to exceed 35 ppm (parts per million) oscillator
frequency error at 25°C, which equates to about ±1.53 minutes per month. With the
calibration bits properly set, the accuracy of each M48T35AV improves to better than
+1/–2 ppm at 25°C.
The oscillation rate of any crystal changes with temperature (see
Most clock chips compensate for crystal frequency and temperature shift error with
cumbersome “trim” capacitors. The M48T35AV design, however, employs periodic counter
correction. The calibration circuit adds or subtracts counts from the oscillator divider circuit
at the divide by 256 stage, as shown in
are blanked (subtracted, negative calibration) or split (added, positive calibration) depends
upon the value loaded into the five calibration bits found in the control register. Adding
counts speeds the clock up, subtracting counts slows the clock down.
The calibration byte occupies the five lower order bits (D4-D0) in the control register 7FF8h.
These bits can be set to represent any value between 0 and 31 in binary form. Bit D5 is the
SIGN bit; '1' indicates positive calibration, '0' indicates negative calibration. Calibration
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Data
D6
D5
D4
D3
D2
10 years
0
0
10 M.
Month
0
10 date
FT
CEB
CB
0
0
10 hours
Hours
10 minutes
Minutes
10 seconds
Seconds
R
S
Calibration
Figure 10 on page
Doc ID 6845 Rev 8
Function/range
BCD format
D1
D0
Year
Year
Month
Date
Date
Day
Century/day
Hours
Minutes
Seconds
Control
Figure 9 on page
16. The number of times pulses
M48T35AV
00-99
01-12
01-31
00-01/01-07
00-23
00-59
00-59
16).