BUY DS1642-150 https://www.utsource.net/itm/p/1478094.html
IC-16K CMOS NVRAM
Description: The DS1642 is a Nonvolatile Timekeeping Circuit with a Real-Time Clock/Calendar and a 256-Byte Battery-Backed CMOS RAM. Features: Real-time clock/calendar with leap year compensation valid up to 2100 Battery-backed 256-byte CMOS RAM Clock/calendar provides seconds, minutes, hours, day, date, month, and year information Two time-of-day alarms Programmable square-wave output Power-fail detect circuitry Single-byte or multiple-byte write capability Low-power CMOS technology 24-pin DIP package Applications: Data logging Security systems Instrumentation Automotive Industrial control Home automation Personal organizers Point-of-sale terminals (For reference only)