"This is a 32768Hz crystal oscillator specifically designed for ultra-low power application. The sole power supply is1.8V, but it can be as low as 1.4V while the oscillator still functions properly. The oscillator works in parallelresonant mode of the crystal. When a 32768Hz quartz crystal is connected to pins XIN32K and XOUT32K, the
oscillator will output 32768Hz square wave, with the average current less than 2uA. This IP supports bypass function mode; it can auto-detect clock inputted from XIN32K."