Microchip MCP79410-I/SN Battery-Backed I2C Real-Time Clock/Calendar SOIC-8

The Microchip MCP79410-I/SN is a highly integrated, battery-backed real-time clock and calendar (RTCC) device featuring integrated SRAM, EEPROM, and protected EEPROM. It provides accurate timekeeping for a wide range of embedded systems, tracking hours, minutes, seconds, days, months, years, and days of the week, with leap year compensation valid through to the year 2399. Operating from a broad 1.8V to 5.5V supply range, it ensures compatibility with various logic levels.

This unprogrammed I²C serial RTCC supports communication speeds of up to 400kHz. It offers two fully programmable alarms that can be configured to trigger on any time/date element, up to and including months. The multifunctional open-drain output pin can be configured to assert on an alarm match, output a selectable frequency square wave, or serve as a general-purpose output.

A key feature is its automatic and seamless switchover to a backup battery supply when main power is lost. This ensures the SRAM contents and the real-time clock continue to operate without interruption. The device precisely logs the times of both switchover to battery and the return of primary power via its power-fail timestamp function.

Design and Reliability

Engineered for reliability, the device is designed to operate with a standard 32.768kHz tuning fork crystal, optimised for crystals with a load capacitance of 6 to 9pF. It includes software write-protection for the EEPROM, supports page writes of up to eight bytes, and boasts an endurance of 1 million erase/write cycles. Housed in a robust 8-lead SOIC package, it is specified for the industrial temperature range of -40°C to +85°C and is AEC-Q100 qualified for demanding automotive applications.