M41T83RMY6E STMicroelectronics, M41T83RMY6E Datasheet - Page 25

• Manufacturer Part Number: M41T83RMY6E
• Description: IC RTC SERIAL W/BATT SW SOX18
• Manufacturer: STMicroelectronics
• Type: Clock/Calendar/Alarmr

Specifications of M41T83RMY6E

• 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: 18-SOX, 18-SOIC with Crystal (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

M41T82-M41T83
3.3
Real-time clock accuracy
The M41T8x is driven by a quartz controlled oscillator with a nominal frequency of
32,768 Hz. The accuracy of the real-time clock is dependent upon the accuracy of the
crystal, and the match between the capacitive load of the oscillator circuit and the capacitive
load for which the crystal was trimmed. Temperature also affects the crystal frequency,
causing additional error (see
The M41T8x provides the option of clock correction through either manufacturing calibration
or in-application calibration. The total possible compensation is typically –93 ppm to +156
ppm. The two compensation circuits that are available are:
1.
2.
Figure 16. Internal load capacitance adjustment
An analog calibration register (12h) can be used to adjust internal (on-chip) load
capacitors for oscillator capacitance trimming. The individual load capacitors C
C
0.25 pF. This translates to a calculated compensation of approximately ±30 ppm (see
Section 3.4.2: Analog calibration (programmable load capacitance) on page
A digital calibration register (08h) can also be used to adjust the clock counter by
adding or subtracting a pulse at the 512 Hz divider stage. This approach provides
periodic compensation of approximately –63 ppm to +126 ppm (see
Digital calibration (periodic counter correction) on page
XO
(see
Figure
16), are selectable from a range of –18 pF to +9.75 pF in steps of
Figure 17 on page
XI
XO
Doc ID 12578 Rev 12
C XO
C XI
Crystal Oscillator
30).
26).
Section 3.4.1:
Clock operation
29).
XI
AI11804
and
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