MP4559 Step-Down Converters Monolithic Power Systems (MPS) MP4559 Step-Down Converters are high-frequency switching regulators with an integrated high-side, high-voltage power MOSFET. The MP4559 series delivers 1.5A output with current mode control for a fast loop response and easy compensation. The wide input range of 3.8V to 55V accommodates many step-down applications, including automotive input environments. 12µA quiescent current in shutdown mode makes the MP4559 series suitable for battery-powered applications. Higher power conversion efficiency is achieved over a wide load range by scaling down the switching frequency under light load conditions.