The DS1672S-33+ is a binary-counter real-time clock (RTC) from Analog Devices, communicating over an I²C / 2-wire serial interface. It tracks time in binary format, not BCD, which simplifies firmware reads when the host expects a straight binary value. Supply range is 2.97 V to 3.63 V on the main rail, with a separate battery-backup input accepting 1.3 V to 3.63 V. The timekeeping current draw maxes at 500 µA at 3.63 V, so the backup battery sees a light load during mains-off periods.
Trickle-charger and backup battery integration
The on-chip trickle-charger allows a rechargeable backup cell to be topped up from the main supply when it is present.