RTC IC With 114x8 NVSRAM And NVSRAM Control, Alarm Wake-up 3V Op On L Version

The CMOS BQ4285E L is Enhanced RTC With NVRAM Control,a low-power Microprocessor peripheral providing a time-of-day Clock and 100-year calendar with alarm features and battery operation. Other features include three maskable interrupt sources, square wave output, and 114 bytes of general nonvolatile storage.
A 32.768kHz output is available for sustaining power-management activities. Wake-up capability is provided by an alarm interrupt, which is active in battery-backup mode.
The BQ4285E L write-protects the Clock calendar, and storage Registers during power failure. A backup battery then maintains data and operates the Clock and calendar.
The BQ4285E L is a fully compatible Real-Time Clock for IBM AT-compatible computers and other applications. The only external components are a 32.768kHz crystal and a backup battery.
The BQ4285E L integrates a battery-backup controller to make a standard CMOS SRAM nonvolatile during power-fail conditions. During power-fail, the BQ4285E L automatically write-protects the external SRAM and provides a VCC output sourced from the Clock backup battery.
By Texas Instruments