MCP7940N 2 Battery-Backed I C Real-Time Clock/Calendar with SRAM Timekeeping Features General Description Real-Time Clock/Calendar (RTCC): The MCP7940N Real-Time Clock/Calendar (RTCC) - Hours, Minutes, Seconds, Day of Week, Day, tracks time using internal counters for hours, minutes, Month, Year seconds, days, months, years, and day of week. Alarms can be configured on all counters up to and - Leap year compensated to 2399 including months. For usage and configuration, the - 12/24 hour modes 2 MCP7940N supports I C communications up to Oscillator for 32.768 kHz Crystals: 400 kHz. - Optimized for 6-9 pF crystals The open-drain, multi-functional output can be On-Chip Digital Trimming/Calibration: configured to assert on an alarm match, to output a - 1 PPM resolution selectable frequency square wave, or as a general - 129 PPM range purpose output. Dual Programmable Alarms The MCP7940N is designed to operate using a Versatile Output Pin: 32.768kHz tuning fork crystal with external crystal load capacitors. On-chip digital trimming can be used - Clock output with selectable frequency to adjust for frequency variance caused by crystal - Alarm output tolerance and temperature. - General purpose output SRAM and timekeeping circuitry are powered from the Power-Fail Time-Stamp: back-up supply when main power is lost, allowing the - Time logged on switchover to and from device to maintain accurate time and the SRAM Battery mode contents. The times when the device switches over to Low-Power Features the back-up supply and when primary power returns are both logged by the power-fail time-stamp. Wide Voltage Range: - Operating voltage range of 1.8V to 5.5V Package Types - Backup voltage range of 1.3V to 5.5V (1) (1) Low Typical Timekeeping Current: MSOP, PDIP , SOIC, TSSOP (1) TDFN - Operating from VCC: 1.2 A at 3.3V X1 1 8 VCC - Operating from battery backup: 925 nA at X1 1 8 VCC 3.0V X2 2 7 MFP X2 2 7 MFP VBAT3S6CL Automatic Switchover to Battery Backup V 3 6 SCL BAT VSS 4 5 SDA User Memory VSS 4 5 SDA 64-byte Battery-Backed SRAM Operating Ranges 2 Note 1: Available in I-temp only. Two-Wire Serial Interface, I C Compatible 2 -I C clock rate up to 400 kHz Temperature Range: - Industrial (I): -40C to +85C - Extended (E): -40C to +125C Automotive AEC-Q100 Qualified Packages 8-Lead MSOP, 8-Lead PDIP, 8-Lead SOIC, 8-Lead 2x3 TDFN and 8-Lead TSSOP 2011-2022 Microchip Technology Inc. and its subsidiares DS20005010J-page 1MCP7940N FIGURE 1-1: TYPICAL APPLICATION SCHEMATIC VCC VCC VCC 8 VCC C 1 X1 X1 6 SCL MCP7940N PIC MCU C 5 2 X2 SDA X2 7 3 VBAT MFP VBAT VSS 4 FIGURE 1-2: BLOCK DIAGRAM VCC Power Control Power-Fail VSS and Switchover Time-Stamp VBAT SCL Control Logic Configuration 2 I C Interface and Addressing SDA Seconds SRAM Minutes X1 32.768 kHz Hours Clock Divider Oscillator X2 Day of Week Digital Trimming Date Square Wave Month Alarms Output Year MFP Output Logic DS20005010J-page 2 2011-2022 Microchip Technology Inc. and its subsidiares 32.768 KHZ