The Always-On domain, over which the power islets emerge, requires a specific panoply of voltage regulators and clocks. The availability of extremely low power oscillators is therefore a must.
In low power modes, low speed clocks are generally used. The qOSC-RC-LP-32k-co.01 - low frequency RC oscillator - is an excellent choice for application combining the needs of ultra-low power consumption and reduced BoM cost.
It can also be suitably combined with a crystal oscillator in order to benefit at once from fast wake-up time of the RC oscillator and from accuracy of the crystal.