AB08X5 Real-Time Clock Family

Date of Issue: October 16, 2014

3.0 x 3.0 mm

Page 4 of 33

Abracon Drawing #453567

Revision: C

The advanced timekeeping feature group supports two additional oscillation modes: 1) RC oscillator mode,

and 2) Autocalibration mode. At only 14 nA, the temperature-compensated RC oscillator mode provides an

even lower current draw than the XT oscillator for applications with reduced frequency accuracy

requirements. A proprietary calibration algorithm allows the AB08X5 to digitally tune the RC oscillator

frequency and the XT oscillator frequency with accuracy as low as 2 ppm at a given temperature. In

Autocalibration mode, the RC oscillator is used as the primary oscillation source and is periodically

calibrated against the XT oscillator. Autocalibration may be done automatically every 8.5 minutes or 17

minutes and may also be initiated via software. This mode enables average current draw of only 22 nA

with frequency accuracy similar to the XT oscillator. The advanced timekeeping feature group also

includes a rich set of input and output configuration options that enables the monitoring of external

interrupts (e.g., pushbutton signals), the generation of clock outputs, and watchdog timer functionality.

Power management features built into the AB08X5 enable it to operate as a backup device in both line-

powered and battery-powered systems. An integrated power control module automatically detects when

main power (VCC) falls below a threshold and switches to backup power (VBAT). 256B of ultra-low

leakage RAM enable the storage of key parameters when operating on backup power. The AB08X5 also

includes digitally-tunable voltage detection on the backup power supply.