BUY M48T18B-150PC1 https://www.utsource.net/itm/p/672379.html
64 Kbit 8Kb x 8 TIMEKEEPER SRAM
Description: The M48T18B-150PC1 is a low-power, low-voltage, 8K x 8-bit nonvolatile static RAM (NVSRAM) with a built-in real-time clock/calendar and power-fail control logic.
Features:
8K x 8-bit nonvolatile static RAM (NVSRAM)
Low-power, low-voltage operation
Built-in real-time clock/calendar
Power-fail control logic
2.0V to 3.6V supply voltage
Access time: 150ns
Package: DIP, STM
Applications:
Automotive
Industrial
Medical
Home appliances
Security systems
Networking and communication systems
(For reference only)