Dallas SRAM clock-chip occupies no memory space

The DS1252W is a 2Mword-by-8 bit nonvolatile SRAM fitted with a "phantom" RTC chip that occupies no memory space and is suited for systems that access the RTC only on power up or rarely during system operation. Typical applications are telecom switches, routers, or RAID systems.

The phantom clock is hidden behind the memory map and provides timekeeping information including hundredths of seconds, seconds, minutes, hours, day, date, month, and year information. It operates in either 12h or 24h format with an AM/PM indicator.

The SRAM is used to store system configuration or crash recovery data. It automatically senses the system power-fail, write protects its SRAM memory, and switches to the lithium battery contained in the DS3800 top hat.

The DS1254W operates over the commercial temperature range of 00C to 700C and is available in a 168-pin BGA package.