BQ4285E Datasheet

Direct clock/calendar replacement for IBM® AT-compatible computers and other applications
114 bytes of general nonvolatile storage
Enhanced features include:
- System wake-up capability?alarm interrupt output active in battery-backup mode
- 2.7-3.6V operation (bq4285L); 4.5-5.5V operation (bq4285E)
- 2kHz output for power management
Automatic backup and write-protect control to external SRAM
Functionally compatible with the DS1285
Less than 0.5µA load under battery operation
14 bytes for clock/calendar and control
BCD or binary format for clock and calendar data
Calendar in day of the week, day of the month, months, and years, with automatic leap-year adjustment
Time of day in seconds, minutes, and hours
- 12- or 24-hour format
- Optional daylight saving adjustment
Programmable square wave out-put
Three individually maskable interrupt event flags:
- Periodic rates from 122us to 500ms
- Time-of-day alarm once per second to once per day
- End-of-clock update cycle
24-pin plastic DIP or SOIC

BQ4285E