A wake detector is simply a circuit which wakes up a microcontroller from its low current sleep state, saving power while anticipating an event which must be processed. In the case of an RF wakeup scheme, substantial power can be saved by allowing the microcontroller to sleep while waiting for a transmitted RF signal. The RF wakeup circuit only interrupts the microcontroller from its sleep state when RF power at the appropriate frequency is detected. An extremely low-power IC that combines an op amp, comparator, and a 0.58V reference can provide some gain, threshold detection, and a logic level signal for a very low power RF wake detector.