The low voltage can be monitored by enabling the PMU(Power Management Unit) and then monitoring the LV IRQ from the TX_IRQ_STATUS_ADR. The LVI event on IRQ pin is automatically disabled whenever the PMU is disabled. If an External Boost Converter is used the low voltage can be monitored only if the controller has analog processing ability. The analog voltage can be fed into a comparator and monitored when it would fall below a set value.In CYRF69103 its not possible as it has no analog processing ability.
REFERENCE DOCUMENT: CYRF69103 datasheet