The MCP79522 SPI RTCC is highly integrated with memory and advanced features normally found in higher priced devices. By starting with a basic real-time clock, digital trimming was added for higher accuracy, a battery switchover for backup power, a timestamp to log power failures and three types of memory, which includes SRAM, EEPROM and a unique ID in a locked section of EEPROM. This ID is preprogrammed with a 64-bit MAC Address, but it can also be ordered blank for the end user to program.

General purpose SPI RTCC with features that target low power, security & communications applications.
• Low Power Operation     -    VCC Min = 1.8V     -    Icc < 5 µA    (Typical Standby Current)
• Low Backup Power     -    VBAT Min = 1.3V     -    Ibat < 700nA       Typical Timekeeping & SRAM Retention Current
• Automatic Battery Switchover with Timestamp     -    VCC to VBAT       (VCC Lost)     -    VBAT to VCC       (VCC Restored)
• Dual configurable alarms with a 0.01 sec count on one alarm    -    IRQ       (VCC or VBAT)
• Clock Out frequencies: 32.768, 8.192 & 4.096 KHz and 1 Hz
• Digital Trimming Range from -255 to + 255 ppm in 1 ppm steps     -    Adjusts up to 22 seconds/day
• EEPROM has 8 Bytes/Page with Block Sector write protection    -    Protect:   None, 1/4, 1/2 or all of array
• Factory standard MAC address programming or custom ID available