BUY DS1211N https://www.utsource.net/itm/p/1122202.html
Nonvolatile Controller X 8 Chip
The Dallas DS1211N is a non-volatile RAM (NVRAM) chip that is used to store data in a computer system. It is a 20-pin DIP (dual in-line package) chip that is used to store data even when the power is turned off. The DS1211N has a capacity of 8K x 8 bits, and it is capable of operating at temperatures ranging from -40°C to +85°C. It is also capable of operating at a voltage range of 3.3V to 5.5V. The DS1211N is used in a variety of applications, including data logging, system configuration, and data storage. It is also used in embedded systems, industrial automation, and medical devices. (For reference only)