BUY M48T86-MH1 https://www.utsource.net/itm/p/11567808.html

Description: The M48T86-MH1 is an 8-pin CMOS real-time clock (RTC) IC from STMicroelectronics. Features: Low power consumption Operating voltage: 2.0V to 5.5V Operating temperature range: -40°C to +85°C Real-time clock accuracy: ±2ppm at 25°C Programmable clock output Battery backup switch Battery voltage monitoring Programmable alarm and timer Programmable power-on reset Programmable watchdog timer Applications: Automotive Industrial Medical Telecom Home appliances Security systems Networking systems (For reference only)