The LM25005 switching regulator features all of the functions necessary to implement an efficient, high voltage buck regulator using a minimum of external components. This easy to use regulator includes a 42V, 160m, N-channel MOSFET, with an output current capability of 2.5 Amps. The regulator control method is based upon current mode control utilizing an emulated current ramp. Current mode control provides inherent line voltage feed-forward, cycle-by-cycle current limiting and ease of loop compensation. The use of an emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable control of very small duty cycles necessary in high input voltage applications. The operating frequency is programmable from 50kHz to 500kHz. An oscillator synchronization pin allows multiple LM25005 regulators to self-synchronize or to be synchronized to an external clock. Additional protection features include: current limit, thermal shutdown and remote shutdown capability. The device is available in a power enhanced TSSOP-20 package featuring an exposed die attach pad to aid thermal dissipation.