PowerWise® subsystems contain multiple devices that form a function that actively adapts its behavior in an effort to reduce power consumption while maintaining high performance. Most RF PA (radio frequency power amplifier) devices will be far better in performance than their worst case data sheet specifications due to high process yield, guard banding and nominal operating temperature (room temp). The circuit above takes advantage of that by monitoring the output power for the desired level using an RF coupler and a power detector to control the supply voltage to the PA. If the power is higher than required, the circuit slews the supply rail to lower the output power of the PA greatly reducing the power consumed in normal operation.