An apparatus, comprising: a system on a chip (SoC) including: a power supply circuit; a power management circuit operatively coupled to the power supply circuit; a first wireless communications circuit (124, 624) configured to receive an RF signal and operatively coupled to the power supply circuit and the power management circuit, and a second wireless communications circuit (126, 626) operatively coupled to the power supply circuit and the power management circuit, and the first wireless communications circuit having, when receiving, a net radio frequency power gain no more than unity before at least one of downconversion of the RF signal or detection of the RF signal, characterized in that the first wireless communications circuit is configured to remain enabled during a low-power mode of the SoC, the second wireless communications circuit is configured to be disabled or duty-cycled during the low-power mode of the SoC, a power consumption of the second wireless communications circuit is greater than a power consumption of the first wireless communications circuit during normal operation of the SoC. a system on a chip (SoC) including: a power supply circuit; a power management circuit operatively coupled to the power supply circuit; a first wireless communications circuit (124, 624) configured to receive an RF signal and operatively coupled to the power supply circuit and the power management circuit, and a second wireless communications circuit (126, 626) operatively coupled to the power supply circuit and the power management circuit, and the first wireless communications circuit having, when receiving, a net radio frequency power gain no more than unity before at least one of downconversion of the RF signal or detection of the RF signal, a power supply circuit; a power management circuit operatively coupled to the power supply circuit; a first wireless communications circuit (124, 624) configured to receive an RF signal and operatively coupled to the power supply circuit and the power management circuit, and a second wireless communications circuit (126, 626) operatively coupled to the power supply circuit and the power management circuit, and the first wireless communications circuit having, when receiving, a net radio frequency power gain no more than unity before at least one of downconversion of the RF signal or detection of the RF signal, characterized in that the first wireless communications circuit is configured to remain enabled during a low-power mode of the SoC, the second wireless communications circuit is configured to be disabled or duty-cycled during the low-power mode of the SoC, a power consumption of the second wireless communications circuit is greater than a power consumption of the first wireless communications circuit during normal operation of the SoC. the first wireless communications circuit is configured to remain enabled during a low-power mode of the SoC, the second wireless communications circuit is configured to be disabled or duty-cycled during the low-power mode of the SoC, a power consumption of the second wireless communications circuit is greater than a power consumption of the first wireless communications circuit during normal operation of the SoC.