The MPQ4559 is a high frequency step-down switching regulator with integrated internal high-side high voltage power MOSFET. It provides 1.5A output with current mode control for fast loop response and easy compensation. The wide 3.8V to 55V input range accommodates a variety of step-down applications, including those in automotive input environment. A 12µA shutdown mode supply current allows use in battery-powered applications. High power conversion efficiency over a wide load range is achieved by scaling down the switching frequency at light load condition to reduce the switching and gate driving losses. The frequency foldback helps prevent inductor current runaway during startup and thermal shutdown provides reliable, fault tolerant operation. By switching at 2MHz, the MPQ4559 is able to prevent EMI (Electromagnetic Interference) noise problems, such as those found in AM radio and ADSL applications. The MPQ4559 is available in small 3mm x 3mm QFN10 and SOIC8 with exposed pad packages.