DS1644P-120+

The DS1644 is a 32k x 8 nonvolatile static RAM with a full function real time clock, which are both accessible in a byte-wide format.
The nonvolatile timekeeping RAM is functionally equivalent to any JEDEC standard 32k x 8 SRAM.
The device can also be easily substituted for ROM, EPROM and EEPROM, providing read/write nonvolatility and the addition of the real time clock function.
The real time clock information resides in the eight uppermost RAM locations.
FEATURES
• Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit and Lithium Energy Source
• Clock Registers are Accessed Identically to the Static RAM.
These Registers are Resident in the Eight Top RAM Locations.
• Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power
• BCD-Coded Year, Month, Date, Day, Hours, Minutes, and Seconds with Leap Year Compensation Valid Up to 2100
• Power-Fail Write Protection Allows for ±10% VCC Power Supply Tolerance
• DS1644 Only (DIP Module) Upward Compatible with the DS1643 Timekeeping RAM to Achieve Higher RAM Density Standard JEDEC Bytewide 32k x 8 Static RAM Pinout
• DS1644P Only (PowerCap Module Board) Surface Mountable Package for Direct Connection to PowerCap Containing Battery and crystal Replaceable Battery (PowerCap) Power-Fail Output Pin-for-Pin Compatible with Other Densities of DS164XP Timekeeping RAM Underwriters Laboratory (UL) Recognized