MCP7940 Datasheet PDF

●The MCP7940N-I/SN is a low-power real-time clock (RTC) IC uses digital timing compensation for an accurate clock/calendar, a programmable output control for versatility and a power sense circuit that automatically switches to the backup supply. Using a low-cost 32.768kHz crystal, it tracks time using several internal registers. For communication, the MCP7940N-I/SN uses the I²C™ bus. The clock/calendar automatically adjusts for months with fewer than 31 days, including corrections for leap years. The clock operates in the 24 or 12-hour format with an AM/PM indicator and settable alarm(s) to the second, minute, hour, day of the week, date or month. Using the programmable CLKOUT, frequencies of 32.768, 8.192 and 4.096kHz and 1Hz can be generated from the external crystal. The device is fully accessible through the serial interface while VCC is between 1.8 and 5.5V, but can operate down to 1.3V for timekeeping and SRAM retention only.

● 12/24 Hour mode battery-backed Real-time Clock/Calendar (RTCC)

● 1PPM Resolution, ±129PPM Range On-chip Digital Trimming/Calibration

● Dual Programmable Alarms

● Clock output with selectable frequency, Alarm output, General Purpose output Versatile Output Pin

● Time logged on switchover to and from Battery Backup Power-Fail Time-Stamp

● 64-byte Battery-backed SRAM

● I²C Clock Frequency up to 400kHz 2-wire Serial Interface, I²C™ Compatible

● Low-power Consumption

● 1.3 to 5.5V Backup Voltage

● Low Typical Timekeeping Current

● 1.2µA at 3.3V Operating from VCC

● 925nA at 3.0V Operating from Battery Backup

● Automatic Switchover to Battery Backup

● 64-byte Battery-backed SRAM User Memory