The RX-4045SAAA3PURESN is a real-time clock module featuring a 4-wire SPI-bus serial interface and a built-in 32.768 kHz crystal unit with high-stability frequency adjustment. It operates across a wide voltage range from 1.7 V to 5.5 V, with a separate timekeeper voltage range of 1.15 V to 5.5 V, and includes a 32.768 kHz clock frequency output via an N-channel open-drain output. The module incorporates time and calendar functions, oscillation stop detection, alarm registers for minute/hour/week and minute/hour, and interrupt output capabilities, with a typical backup current consumption of only 0.48 µA at 3 V. The device is housed in a 14-pin SOP package and is RoHS compliant, making it suitable for battery-backed timekeeping, data logging, and embedded systems requiring accurate time management with minimal power consumption.