Hello,
Wake up from Deep Power Down mode is exited through the reset sequence [Hardware Reset], this power mode is the lowest disponible. [Section 3.4 Wake up time]
The example from SDK "power_mode_switch_k4" has the option to enter 2 available DeepPowerDown modes and select a wakeup source, using a button [ SW3 in KW45B41Z-EVK ] or wakeup from VBAT [ SW5 in KW45B41Z-EVK ].
Could this example match what you want to implement with KW45?
Could you help us confirm, Are you using the KW45B41Z-EVK or a custom board?
Best Regards
Luis