Real time clock IC is super-low power

The AB1805 real time clock IC is one of a family of ultra-low power ICs that keep time even when power is lost. With a supply current of 14 nA, when using the RC oscillator, the IC can be powered from a super capacitor for extended operation without power.

The chip features a 32.768 kHz crystal oscillator with integrated load capacitor/resistor, auto calibration, a watch dog, 256-bits of RAM, and a VBAT switch. For highly accurate (2 ppm) time backup at only 55 nA supply current, the IC can use a high quality crystal. The chip has an I² C interface and comes in a 3.0 x 3.0 mm QFN-16 package. It costs only $0.82 ea/3,000.