M48T254V is a 3.3V, 16 Mbit (2 Mb x 8 bit) TIMEKEEPER® SRAM WITH PHANTOM CLOCK with the following features: 3.3V ± 10%, integrated ultra-low power SRAM, real-time clock, power-fail control circuit, battery and crystal, the real-time clock keeps track of tenths / hundredths of seconds, seconds, minutes, hours, days, date, months, and years. The clock function is transparent to RAM operation. Precision power monitoring and power switching circuitry, automatic write-protection when VCC is out-of-tolerance, power-fail deselect voltage: VCC = 3.3V ± 10%; 2.8V ≤ VPFD ≤ 2.97V, battery low (BL), 10 years of data retention and battery operation, SNAPHAT housing (battery/crystal) is replaceable, 100ns access (read = write).