MCP7951X/MCP7952X Battery-Backed SPI Real-Time Clock/Calendar 128-Bit Protected EEPROM Area: Device Selection Table - Robust write unlock sequence SRAM EEPROM Part Number Unique ID - EUI-48 MAC address (MCP795X1) (Bytes) (Kbits) - EUI-64 MAC address (MCP795X2) MCP79510 64 1 Blank MCP79520 64 2 Blank Operating Ranges MCP79511 64 1 EUI-48 SPI Serial Interface: MCP79521 64 2 EUI-48 - SPI clock rate up to 5 MHz MCP79512 64 1 EUI-64 Temperature Range: MCP79522 64 2 EUI-64 - Industrial (I): -40C to +85C Timekeeping Features Packages Real-Time Clock/Calendar (RTCC): 10-Lead MSOP and TDFN - Hours, minutes, seconds, hundredth of seconds, day of week, date, month, year Package Types (not to scale) - Leap year compensated to 2399 - 12/24-hour modes MSOP/TDFN Oscillator for 32.768 kHz Crystals: - Optimized for 6-9 pF crystals X1 1 10 VCC On-Chip Digital Trimming/Calibration: X2 2 9 MFP - 1 ppm resolution VBAT 3 8 SCK - 259 ppm range Dual Programmable Alarms 4 7 CS SO Clock Output Function with Selectable Frequency 5 6 SI VSS Power-Fail Timestamp: - Time logged on switchover to and from Battery mode Note: MCP795XX is used in this document as a Low-Power Features generic part number for the MCP7951X Wide Voltage Range: and MCP7952X devices. - Operating voltage range of 1.8V to 3.6V - Backup voltage range of 1.3V to 3.6V Low Typical Timekeeping Current: - Operating from VCC: 1.2 A at 3.0V - Operating from VBAT: 1.0 A at 3.0V Automatic Switchover to Battery Backup User Memory 64-Byte Battery-Backed SRAM 1 Kbit or 2 Kbit EEPROM: - Software write-protect - Page write up to 8 bytes - Endurance: one million erase/write cycles 2012-2018 Microchip Technology Inc. DS20002300C-page 1 MCP795XXMCP7951X/MCP7952X Description The MCP795XX Real-Time Clock/Calendar (RTCC) tracks time using internal counters for hours, minutes, seconds, hundredth of 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 MCP795XX supports SPI communications up to 5 MHz. The MCP795XX is designed to operate using a 32.768kHz 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 backup supply and when primary power returns are both logged by the power-fail timestamp. The MCP795XX features 128 bits of EEPROM which is only writable after an unlock sequence, making it ideal for storing a unique ID or other critical information. The MCP795X1 and MCP795X2 are preprogrammed with EUI-48 and EUI-64 addresses, respectively. Custom programming is also available. The MCP795XX has a shared pin for outputting a selectable frequency square wave or alarm signals. FIGURE 1-1: TYPICAL APPLICATION SCHEMATIC VCC VCC VCC 10 VCC C 1 X1 X1 4 CS C 8 2 X2 X2 SCK 6 3 MCP795XX SI VBAT PIC MCU VBAT 7 SO 9 MFP VSS 5 2012-2018 Microchip Technology Inc. DS20002300C-page 2 32.768 KHZ