BUY DS1307N https://www.utsource.net/itm/p/1317299.html
64 x 8, Serial, I2C Real-Time Clock
Description: The DS1307N is a low-power real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. Features: - 56-byte, battery-backed, nonvolatile (NV) RAM - Timekeeping accuracy of ±2 minutes per year at 25°C - Programmable square-wave output signal - Programmable alarm - Programmable clock output - Automatic power-fail detect and switch circuitry - Low-power operation Applications: - Automotive - Industrial - Medical - Consumer - Wearable (For reference only)