An amplifier can advantageously use a power supply voltage source that provides a voltage greater than all breakdown voltages of the process associated with transistors of the amplifier. Specifically, cascoded configurations can be used to reduce the gate-drain and source-drain voltages of “at-risk” transistors in the amplifier. During a power down mode, a bias shunt of the amplifier can isolate certain nodes from the voltage sources. At the same time, a charge circuit of the amplifier can charge those nodes to a predetermined voltage, thereby minimizing stress to the at-risk transistors during the power down mode. A multi-flavor power down signal generator circuit can advantageously generate the appropriate power down signals for driving various transistors of the amplifier during the power down mode.