Section 30.5 in the KL03 reference manual (rev 4) indicates that there is a settling time that you must wait before using the voltage reference to ensure accurate results. The reference manual says that this time is specified by Tchop_osc_stup, which is defined in the datasheet. I can find no mention of the Tchip_osc_step parameter in the datasheet for KL03.
Am I missing something, or should this be published in the datasheet?
From section 30.5:
When the chop oscillator is enabled, the settling time of the internal bandgap reference is defined by Tchop_osc_stup (chop oscillator start up time). You must wait this time (Tchop_osc_stup) after the internal bandgap has been enabled to ensure the VREF internal reference voltage has stabilized.