The DS1340Z-3+ is a low-power real-time clock (RTC) that tracks time in HH:MM:SS (24-hour format) and date in YY-MM-DD-dd format, communicating over an I²C (2-wire serial) interface. The device includes a trickle-charger for charging a backup battery or supercapacitor, and automatically handles leap-year corrections through 2099.
Battery-backup and supply considerations
A separate battery-supply pin accepts 1.3 V to 3.7 V, allowing a 3 V lithium coin cell or a 2.5 V supercap to keep timekeeping alive when the main rail drops. The trickle-charger feature means the backup capacitor can be recharged on the board — useful in designs where the battery is not user-replaceable and the product must survive years of intermittent power.