Datasheet

Contents
1 Description ........................................................................2
2 Operation..........................................................................7
2.1 2-wire bus characteristics........................................................7
2.1.1 Bus not busy ............................................................7
2.1.2 Start data transfer ........................................................7
2.1.3 Stop data transfer ........................................................7
2.1.4 Data valid ..............................................................7
2.1.5 Acknowledge............................................................7
2.2 READ mode...................................................................8
2.3 WRITE mode ..................................................................9
3 Clock operation...................................................................11
3.1 RTC registers.................................................................11
3.2 Calibrating the clock ...........................................................16
3.3 Setting alarm clock registers ....................................................17
3.4 Watchdog timer ...............................................................18
3.5 Watchdog output (WDO - M41T65 only) ..........................................18
3.6 Square wave output (M41T62/64)................................................19
3.7 Full-time 32 KHz square wave output (M41T64)....................................19
3.8 Century bits ..................................................................20
3.9 Leap year ....................................................................20
3.10 Output driver pin (M41T62/65)...................................................20
3.11 Oscillator stop detection ........................................................20
3.12 Initial power-on defaults ........................................................21
4 Maximum ratings .................................................................22
5 DC and AC parameters ...........................................................23
6 Package information..............................................................27
6.1 QFN16 package information ....................................................27
6.2 LCC8 package information......................................................30
7 Packing information ..............................................................33
M41T62, M41T64, M41T65
Contents
DS3840 - Rev 24
page 38/42