With input voltage range up to 75 V, four high-voltage, non-synchronous buck controllers from National Semiconductor feature 85 percent peak efficiency when powering low voltage loads from a high voltage supply. The controllers can regulate output voltages as low as 1.2 V at load currents in excess of 5 A. Each offers programmable switching frequency up to 1 MHz using a single resistor. The controllers feature feature an emulated current-mode (ECM) control PWM control topology. From $0.85 in 1,000-unit quantities.