BUY M41T00SM6 https://www.utsource.net/itm/p/6422781.html

Description: Real-Time Clock Features: Low power consumption I2C bus interface Programmable clock output Battery switchover Low voltage detection Programmable alarm Time stamp counter Operating temperature range: -40°C to +85°C Package: SOP, ST Applications: Automotive Industrial Medical Home appliances Portable devices Wearable devices Networking devices (For reference only)