The MCP7940M I2CTM compatible real-time clock/calendar (RTCC) includes SRAM and a digital trimming circuit for accuracy which is normally found in higher priced devices. Using a low-cost 32,768 kHz crystal or other clock source, time is tracked in either a 12-hour or 24-hour format with an AM/PM indicator and timing to the second, minute, hour, day of the week, day, month and year. As an interrupt or wakeup signal, a multifunction open drain output can be programmed as an Alarm Out or as a Clock Out that supports 4 selectable frequencies.

Timekeeping

  Real-Time Clock/Calendar (RTCC)

  Hours, Minutes, Seconds, Day of Week, Day, Month, Year

  Leap year compensated  to 2399

  12/24 hour modes

  On-Chip Digital Trimming/Calibration

  1 PPM Resolution

  ±129 PPM Range

  Dual Programmable Alarms

  Versatile Output Pin

  Clock output with selectable frequency

  Alarm output

  General Purpose output

  64 Bytes SRAM

  2-Wire Serial Interface, I2C™Compatible

  I2C Clock Frequency up to 400 kHz

Low-Power

  Wide Voltage Range

  Operating Voltage 1.8V to 5.5V

  Low Typical Timekeeping Current