M41T00CAP Serial access real-time clock (RTC) with integral backup battery and crystal Datasheet - production data Operating temperature of 0 to 70 C Self-contained battery and crystal in CAPHAT DIP package RoHS compliant Lead-free second level interconnect 24 Description 1 The M41T00CAP is a low-power serial real-time clock (RTC) with integral battery and crystal in PCDIP24 STs 24-pin CAPHAT package. It includes a Battery/Crystal CAPHAT crystal controlled, 32.768 kHz oscillator and has a built-in power sense circuit which detects power failures and automatically switches to the backup battery when a power failure occurs. Features Eight registers comprise the clock/calendar Real-time clock (RTC) with backup battery function and are configured in binary-coded integrated into package decimal (BCD) format. Addresses and data are Uses M41T00S enhanced RTC with transferred serially via an industry standard, two precision switchover reference 2 2 line, 400 kHz, bidirectional I C interface. The 400 kHz I C serial interface built-in address register is incremented Automatic switchover and deselect circuitry automatically after each WRITE or READ data with fixed reference voltage byte. The internal lithium coin cell contains ample V = 2.7 to 5.5 V operating voltage CC energy to sustain timekeeping operation for 10 range years in the absence of system power. The eight 2.6 V (typ) power-fail deselect clock address locations contain the century, year, (switchover) threshold month, date, day, hour, minute, and second in Counters for seconds, minutes, hours, day, 24-hour BCD format. Corrections for the number date, month, year and century of days in a month, including leap year, are made Software clock calibration automatically (leap year valid up to year 2100). Low operating current of 300 A Oscillator stop detection Battery backup October 2014 DocID014557 Rev 6 1/24 www.st.com This is information on a product in full production. Contents M41T00CAP Contents 1 Overview .......................................................................................... 5 1.1 Pin connections ................................................................................. 6 1.2 Pin description ................................................................................... 6 2 Operation ......................................................................................... 7 2.1 Wire bus characteristics .................................................................... 7 2.2 Bus not busy ..................................................................................... 7 2.3 Start data transfer ............................................................................. 7 2.4 Stop data transfer .............................................................................. 7 2.5 Data valid .......................................................................................... 8 2.6 Acknowledge ..................................................................................... 8 2.7 READ mode ...................................................................................... 9 2.8 WRITE mode ................................................................................... 11 2.9 Data retention mode ........................................................................ 11 3 Clock operation ............................................................................. 12 3.1 Clock registers ................................................................................ 13 3.2 Calibrating the clock ........................................................................ 13 3.3 Century bit ....................................................................................... 14 3.4 Oscillator fail detection .................................................................... 15 3.5 Output driver pin .............................................................................. 15 3.6 Initial power-on default .................................................................... 15 4 Maximum ratings ........................................................................... 16 5 DC and AC parameters ................................................................. 17 6 Package information ..................................................................... 20 6.1 PCDIP24 package ........................................................................... 20 7 Part numbering .............................................................................. 21 8 Environmental information ........................................................... 22 9 Revision history ............................................................................ 23 2/24 DocID014557 Rev 6