M41T82RM6F STMicroelectronics, M41T82RM6F Datasheet - Page 31

• Manufacturer Part Number: M41T82RM6F
• Description: IC RTC SERIAL W/BATT SW 8-SOIC
• Manufacturer: STMicroelectronics
• Type: Clock/Calendar/Alarmr

Specifications of M41T82RM6F

• Memory Size: 32B
• Time Format: HH:MM:SS:hh (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8279-2; M41T82RM6F

M41T82-M41T83
Note:
Figure 18. Clock accuracy vs. on-chip load capacitance
Analog Calibration
NET EQUIV. LOAD
CAP., C
register 0x12
C
OFFSET TO
100.0
The on-chip capacitance can be calculated as follows:
where ACS is the sign.
For example:
●
●
●
With the analog calibration adjusted to its lowest value, the oscillator will see a minimum of
3.5 pF load capacitance as shown on the bottom row of
These are typical values, and the total load capacitance seen by the crystal will include
approximately 1-2 pF of package and board capacitance in addition to the analog calibration
register value.
Any invalid value of analog calibration will result in the default capacitance of 25 pF.
The combination of analog and digital trimming can give up to –93 to +156 ppm of the total
adjustment.
Figure 18
value. This curve may vary with different crystals, so it is good practice to evaluate the
crystal to be used with an M41T8x device before establishing the adjustment values for the
application in question.
-20.0
XI
Value, AC,
80.0
60.0
40.0
20.0
LOAD
, C
0.0
XO
C
C
C
LOAD
LOAD
LOAD
, (pF)
(pF)
represents a typical curve of clock ppm adjustment versus the analog calibration
SLOWER
FASTER
(12h = x0000000) = 12.5 pF
(12h =11001000) = 3.5 pF (sign is negative)
(12h = 00100111) = 17.4 pF
0xC8 0xBC
-18.0 -15.0
3.5
C
LOAD
5.0
=
2
1
Doc ID 12578 Rev 12
[
ACS
DECREASING LOAD CAP.
(
-10.0
0xA8
AC
7.5
: 6
AC
0
value
0x94
-5.0
10
,
decimal
On-Chip
C
Table
XI
XI
)
0x00
⋅
12.5
0.0
. 0
25
7.
INCREASING LOAD CAP.
Oscillator
+
Crystal
C
25
LOAD
]
pF
C
=
0x14
XO
5.0
15
C
C
XI
XI
XO
+ C
*
Clock operation
C
XO
XO
0x27
9.75
17.4
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