BUY DS1689S https://www.utsource.net/itm/p/413638.html
3-Volt/5-Volt Serialized Real-Time Clock with NV RAM Control
The DS1689S is a Real-Time Clock (RTC) IC manufactured by Dallas Semiconductor. It is a low-power, low-cost, and highly accurate timekeeping device that can be used in a variety of applications. Description: The DS1689S is a low-power Real-Time Clock (RTC) IC that provides a highly accurate timekeeping solution. It features a built-in oscillator, a battery-backed SRAM, and a 32kHz crystal. The device is available in a 28-pin SOP package. Features: Low-power CMOS design Battery-backed SRAM 32kHz crystal Built-in oscillator Low-cost and highly accurate timekeeping 28-pin SOP package Applications: The DS1689S can be used in a variety of applications, including: Automotive Industrial Medical Networking Security Wearable devices (For reference only)