M41T82RM6F datasheet(45/61 Pages) STMICROELECTRONICS

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M41T82-M41T83

Clock operation

Doc ID 12578 Rev 12

45/61

3.17

OTP bit operation (M41T83 in SOX18 package only)

When the OTP (one time programmable) bit is set to a '1,' the value in the internal OTP

registers will be transferred to the analog calibration register (12h) and are “Read only.” The

OTP value is programmed by the manufacturer, and will contain the calibration value

necessary to achieve ±5 ppm at room temperature after two SMT reflows. This clock

accuracy can then be guaranteed to drift no more than ±3 ppm the first year, and ±1 ppm for

each following year due to crystal aging.

If the OTP bit is set to 0, the analog calibration register will become a WRITE/READ register

and function like standard SRAM memory cells, allowing the user to implement any desired

value of analog calibration.

When the user sets the OTP bit, they need to wait for approximately 8 ms before the analog

registers transfer the value from the OTP to the analog registers due to the OTP read

operation.

M41T82RM6F Datasheet(PDF) 45 Page - STMicroelectronics