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 Oscillator for 32.768 kHz Crystals: Packages: - Optimized for 6-9 pF crystals 8-Lead SOIC, MSOP, TSSOP, PDIP and 2x3 On-Chip Digital Trimming/Calibration: TDFN - 1 PPM resolution General Description: - 129 PPM range The MCP7940N Real-Time Clock/Calendar (RTCC) Dual Programmable Alarms tracks time using internal counters for hours, minutes, Versatile Output Pin: seconds, days, months, years, and day of week. - Clock output with selectable frequency Alarms can be configured on all counters up to and - Alarm output including months. For usage and configuration, the 2 MCP7940N supports I C communications up to 400 - General purpose output kHz. Power-Fail Time-Stamp: The open-drain, multi-functional output can be - Time logged on switchover to and from configured to assert on an alarm match, to output a Battery mode selectable frequency square wave, or as a general Low-Power Features: purpose output. Wide Voltage Range: The MCP7940N is designed to operate using a 32.768 - Operating voltage range of 1.8V to 5.5V kHz tuning fork crystal with external crystal load - Backup voltage range of 1.3V to 5.5V capacitors. On-chip digital trimming can be used to adjust for frequency variance caused by crystal Low Typical Timekeeping Current: tolerance and temperature. - Operating from VCC: 1.2 A at 3.3V SRAM and timekeeping circuitry are powered from the - Operating from battery backup: 925 nA at back-up supply when main power is lost, allowing the 3.0V device to maintain accurate time and the SRAM Automatic Switchover to Battery Backup contents. The times when the device switches over to User Memory: the back-up supply and when primary power returns are both logged by the power-fail time-stamp. 64-byte Battery-Backed SRAM 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. 2010-2014 Microchip Technology Inc. DS20005010F-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 DS20005010F-page 2 2010-2014 Microchip Technology Inc. 32.768 KHZ