The TPS9103 is a highly integrated power supply for depletion-mode GaAs power amplifiers (PA) in cellular handsets and other wireless communications equipment. Functional integration and low-profile packaging combine to minimize circuit-board area and component height requirements. The device includes: a p-channel MOSFET configured as a high-side switch to control the application of power to the PA; a driver for the high-side switch with a logic-compatible input; a charge pump to provide negative gate-bias voltage; and logic to prevent turn-on of the high-side switch until gate bias is present. The high-side switch has a typical on-state resistance of 135 m.