The DS1672 low-voltage serial timekeeping chip incorporates a 32-bit counter and power-monitoring functions. The 32-bit counter is designed to count seconds and can be used to derive time-of-day, week, month, and year by using a software algorithm. A precision, temperature-compensated reference and comparator circuit monitors the status of VCC. When an out-of-tolerance condition occurs, an internal power-fail signal is generated that forces the reset to the active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for 250ms to allow the power supply and processor to stabilize.

32-Bit Counter
I²C Serial Interface
Automatic Power-Fail Detect and Switch Circuitry
Power-Fail Reset Output
Low-Voltage Oscillator Operation (1.3V min)
Trickle-Charge Capability