MCP7940N-I/SN

MCP7940N-I/SN is a battery-backed I2C™ real-time clock/calendar with SRAM. It tracks time using internal counters for hours, minutes, seconds, days, months, years, and days of the week. Alarms can be configured on all counters up to and including months. For usage and configuration, the MCP7940N supports I2C communications up to 400KHz. The open-drain, multi-functional output can be configured to assert on an alarm match, to output a selectable frequency square wave, or as a general-purpose output. It is designed to operate using a 32.76KHz 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 the main power is lost, allowing the device to maintain accurate time and the SRAM contents.

• Leap year compensated to 2399, 12/24 hour modes
• Dual programmable alarms, 64-byte Battery-Backed SRAM
• Clock output with selectable frequency, alarm output, general purpose output
• Time logged on switchover to and from battery mode, automatic switchover to battery backup
• On-chip digital trimming/calibration: ±1PPM resolution, ±129PPM range
• Wide operating voltage range from 1.8V to 5.5V
• Low typical timekeeping current from VCC is 1.2µA at 3.3V (Operating)
• Clock frequency is 100KHz max (VCC = +1.8V to 5.5V TA = -40°C to +85°C)
• VCC fall time is 300µs min (VCC = +1.8V to 5.5V TA = -40°C to +85°C)
• SOIC package, industrial temperature range from -40 to 85°C