The RX-8564LCB0PURESN is a real-time clock module featuring an I2C-Bus interface (400 kHz) with an integrated frequency-adjusted 32.768 kHz crystal unit. It operates across a wide voltage range of 1.8V to 5.5V for normal operation and 1.0V to 5.5V in timekeeper mode, with exceptionally low backup current consumption of 275 nA at 3.0V typical. The module includes comprehensive timekeeping functions such as full calendar, alarm, timer, and power supply voltage monitoring, along with a 32.768 kHz frequency output with C-MOS control capability. It is housed in a 12-pin VSOJ package and operates reliably across -40°C to +85°C, making it suitable for portable devices, battery-backed systems, and applications requiring precise time management with minimal power draw.