MICROCHIP MCP79410-I/MS

The MCP7941X Real-Time Clock/Calendar (RTCC) tracks time using internal counters for hours, minutes, seconds, days, months, years, and day of week. Alarms can be configured on all counters up to and including months. For usage and configuration, the MCP7941X supports |²C〉 communications up to 400 kHz. The open-drain, multi-functional output can be configured to assert on an alarm match, to output a selectable frequency square wave or as a general purpose output. The MCP7941X is designed to operate using a 32.768 kHz tuning fork crystal with external crystal load capacitors. On-chip digital trimming can be used to adjust for frequency variance caused by crystal tolerance and temperature. SRAM and timekeeping circuitry are powered from the backup supply when main power is lost, allowing the device to maintain accurate time and the SRAM contents. The times when the device switches over to the back-up supply and when primary power returns are both logged by the power-fail time-stamp. The MCP7941X features 1 Kbit of internal nonvolatile EEPROM with software write-protectable regions. There is an additional 64 bits of protected nonvolatile memory which is only writable after an unlock sequence, making it ideal for storing a unique ID or other critical information. The MCP79411 and MCP79412 are pre-programmed with EUI-48 and EUI-64 addresses, respectively. Custom programming is also available.

• Real-Time Clock/Calendar (RTCC):
  • Hours, minutes, seconds, day of week, day, month, year
  • Leap year compensated to 2399
  • 12/24-hour modes
• Oscillator for 32.768 kHz Crystals:
  • Optimized for 6 - 9 pF crystals
• 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
• Power-Fail Time-Stamp:
  • Time logged on switchover to and from Battery mode
• Wide Voltage Range:
  • Operating voltage range of 1.8V to 5.5V
  • Backup voltage range of 1.3V to 5.5V
• Low Typical Timekeeping Current:
  • Operating from VCC: 1.2 μA at 3.3V
  • Operating from VBAT: 925 nA at 3.0V
• Automatic Switchover to Battery Backup
• 64-Byte Battery-Backed SRAM
• 1 Kbit EEPROM Memory:
  • Software write-protect
  • Page write up to eight bytes
  • Endurance: 1M Erase/Write cycles
• 64-Bit Protected EEPROM Area:
  • Robust write unlock sequence
  • EUI-48rw MAC address (MCP79411)
  • EUI-64TM MAC address (MCP79412)
• 2-Wire Serial Interface, |²C Compatible:
  • |²C〉 clock rate up to 400 kHz
• Temperature Range:
  • Industrial (I): -40°C to +85°C