DESCRIPTION
The M48T559Y TIMEKEEPER® RAM is an 8K x 8 non-volatile static RAM and real time clock. The monolithic chip is available in the SNAPHAT package to provide a highly integrated battery backedup memory and real time clock solution.

■ SOFTWARE and HARDWARE RESET for WATCHDOG TIMER
■ REGISTER COMPATIBLE with M48T59 TIMEKEEPER SRAM
■ ADDRESS/DATA MULTIPLEXED I/O PINS
■ WATCHDOG TIMER - MONITORS OUT of CONTROL PROCESSOR or HUNG BUS
■ ALARM with WAKE-UP in BATTERY MODE
■ INTEGRATED ULTRA LOW POWER SRAM, REAL TIME CLOCK, POWER-FAIL CONTROL CIRCUIT and BATTERY
■ FREQUENCY TEST OUTPUT for REAL TIME CLOCK
■ AUTOMATIC POWER-FAIL CHIP DESELECT and WRITE PROTECTION
■ WRITE PROTECT VOLTAGE (VPFD = Power-fail Deselect Voltage): – M48T559Y: 4.2V ≤ VPFD ≤ 4.5V
■ PACKAGING INCLUDES a 28-LEAD SOIC and SNAPHAT® TOP (to be Ordered Separately)
■ SOIC PACKAGE PROVIDES DIRECT CONNECTION for a SNAPHAT TOP CONTAINS the BATTERY and CRYSTAL
■ MICROPROCESSOR POWER-ON RESET (Valid even during battery back-up mode)
■ PROGRAMMABLE ALARM OUTPUT ACTIVE in the BATTERY BACK-UP MODE