An integrated power management unit (PMU) is presented addressing the special requirements arising from the integration of wake-up receivers into conventional wireless transceivers. It realizes an ultra low power sleep state by establishing one single always-on power domain, whose generation circuitry features an adaptive current consumption dependent on the current state of operation. The proposed design was fabricated in a 130nm CMOS technology. In sleep state the proposed PMU consumes 15.2µA resulting in a total consumption of 20.7µA from a 1.4V supply for the entire transceiver system. Additionally, an accelerated PMU start-up was implemented providing a faster system response after wake-up from sleep state.