BUY DS1216D https://www.utsource.net/itm/p/844810.html
Using the Dallas Phantom Real Time Clocks256K/1MSRAM
Description: The DS1216D is a 32-pin CMOS Nonvolatile SRAM manufactured by Dallas Semiconductor. Features: Low power consumption Fast access time Low standby current Data retention for 10 years 32-pin DIP package TTL compatible 4K x 8 bit nonvolatile SRAM Automatic write protection Data protection against power loss Automatic write verification Applications: Automotive systems Industrial control systems Data logging Battery-backed memory Portable instrumentation Security systems Medical instrumentation (For reference only)