MCP7940N 2 Battery-Backed I C Real-Time Clock/Calendar with SRAM Timekeeping Features Operating Ranges 2 2-Wire Serial Interface, I C Compatible Real-Time Clock/Calendar (RTCC): 2 -I C clock rate up to 400 kHz - Hours, Minutes, Seconds, Day of Week, Day, Month, Year Temperature Range: - Leap year compensated to 2399 - Industrial (I): -40C to +85C - Extended (E): -40C to +125C - 12/24 hour modes Automotive AEC-Q100 Qualified Oscillator for 32.768 kHz Crystals: - Optimized for 6-9 pF crystals Packages On-Chip Digital Trimming/Calibration: 8-Lead SOIC, MSOP, TSSOP, PDIP and 2x3 - 1 PPM resolution TDFN - 129 PPM range General Description Dual Programmable Alarms The MCP7940N Real-Time Clock/Calendar (RTCC) Versatile Output Pin: tracks time using internal counters for hours, minutes, - Clock output with selectable frequency seconds, days, months, years, and day of week. - Alarm output Alarms can be configured on all counters up to and - General purpose output including months. For usage and configuration, the 2 MCP7940N supports I C communications up to 400 Power-Fail Time-Stamp: kHz. - Time logged on switchover to and from Battery mode The open-drain, multi-functional output can be configured to assert on an alarm match, to output a Low-Power Features selectable frequency square wave, or as a general Wide Voltage Range: purpose output. - Operating voltage range of 1.8V to 5.5V The MCP7940N is designed to operate using a 32.768 - Backup voltage range of 1.3V to 5.5V kHz tuning fork crystal with external crystal load Low Typical Timekeeping Current: capacitors. On-chip digital trimming can be used to adjust for frequency variance caused by crystal - Operating from VCC: 1.2 A at 3.3V tolerance and temperature. - Operating from battery backup: 925 nA at 3.0V SRAM and timekeeping circuitry are powered from the back-up supply when main power is lost, allowing the Automatic Switchover to Battery Backup device to maintain accurate time and the SRAM User Memory contents. The times when the device switches over to 64-byte Battery-Backed SRAM the back-up supply and when primary power returns are both logged by the power-fail time-stamp. Package Types (1) (1) SOIC, MSOP, TSSOP , PDIP (1) TDFN X1 1 8 VCC X1 1 8 VCC X2 2 7 MFP X2 2 7 MFP VBAT3S6CL V 3 6 SCL BAT VSS 4 5 SDA VSS 4 5 SDA Note 1: Available in I-temp only. 2011-2019 Microchip Technology Inc. DS20005010H-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 MFP VBAT 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 2011-2019 Microchip Technology Inc. DS20005010H-page 2 32.768 KHZ