The MCP79402 general purpose I²C^TM Compatible real-time clock/calendar (RTCC) is highly integrated with memory and advanced features normally found in higher priced devices. These features include a battery switchover circuit for backup power, a timestamp to log power failures and digital trimming for accuracy. 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. In addition to the SRAM memory, there a unique ID that is factory programmed in a locked section of EEPROM with a MAC Address. This ID can also be unlocked and reprogrammed by the end user.

General purpose RTCC with features that target low power and smart energy applications.

• Low Power Operation
  • VCC Min = 1.8V
  • Icc < 5 µA Typical Dynamic Current
• Low Backup Power
  • VBAT Min = 1.3V
  • Ibat < 700nA Typical Timekeeping & SRAM Retention Current
• Automatic Battery Switchover with Timestamp
  • VCC to VBAT (power lost)
  • VBAT to VCC (power restored)
• Dual alarms with single Interrupt Output that operates on VCC or VBAT
• Clock Out frequencies of 32.768, 8.192 & 4.096 KHz and 1 Hz
• Digital Trimming Range from -127 to + 127 ppm in 1 ppm steps
  • 1 ppm is approximately 86 milliseconds/day
• EEPROM uses 8 bytes/page with Block Sector write protection
  • Protect none, 1/4, 1/2 or all of array
• Unique ID is factory programmed with MAC Address