M48T251Y Datasheet PDF - STMicroelectronics

SUMMARY DESCRIPTION
The M48T251Y/V TIMEKEEPER® RAM is a 512Kbit x 8 non-volatile static RAM and real time clock organized as 524,288 words by 8 bits. The special DIP package provides a fully integrated battery back-up memory and real time clock solution. In the event of power instability or absence, a self-contained battery maintains the timekeeping operation and provides power for a CMOS static RAM. Control circuitry monitors VCC and invokes write protection to prevent data corruption in the memory and RTC.

FEATURES SUMMARY
â–  5.0V OR 3.3V OPERATING VOLTAGE
â–  REAL TIME CLOCK KEEPS TRACK OF TENTHS/HUNDREDTHS OF SECONDS, SECONDS, MINUTES, HOURS, DAYS, DATE OF THE MONTH, MONTHS, AND YEARS
â–  AUTOMATIC LEAP YEAR CORRECTION VALID UP TO THE YEAR 2100
â–  AUTOMATIC SWITCH-OVER AND DESELECT CIRCUITRY
â–  CHOICE OF POWER-FAIL DESELECT VOLTAGES: (VPFD = Power-fail Deselect Voltage):
   – M48T251Y: 4.25V ≤ VPFD ≤ 4.50V
   – M48T251V: 2.80V ≤ VPFD ≤ 2.97V
â–  FULL 10% VCC OPERATING RANGE
■ OVER 10 YEARS’ DATA RETENTION IN THE ABSENCE OF POWER
â–  WATCH FUNCTION IS TRANSPARENT TO RAM OPERATION
â–  512K x 8 NV SRAM DIRECTLY REPLACES VOLATILE STATIC RAM OR EEPROM