Demonstration circuit 423 is a 60V, 500kHz, 1A load current, monolithic step-down DC/DC switching converter using the LT1956. With its wide input voltage range, 1.5A internal power switch, and thermally enhanced package, the LT1956 is a very versatile and powerful IC for DC/DC converters that require compact space and a wide variety of input voltage ranges. The constant 500kHz switching frequency allows all of the components to be small, surface mount devices. The currentmode control topology creates fast transient response and good loop stability with a minimum number of external compensation components and the use of ceramic input and output capacitors. The low resistance internal power switch (0.2?) maintains high efficiencies >75% and up to 90%. The SHDN pin and 25µA shutdown current extends battery life. The wide VIN range of the LT1956 allows steady state input voltages from 7.5V input up to 25V input. The LT1956 is capable of steady state operation of up to 60V if the output voltage is set higher than 5V and the duty cycle remains high enough (typically above 25%). Minimum on-time and maximum output power at high input voltages may have thermal restrictions (please see datasheet for more details). However, with 5V output, the LT1956 is designed for transient operation up to 60V. Synchronization of switching frequencies up to 700kHz is possible. Demonstration Circuit 423 is designed for 7.5V to 25V input (with up to 60V transient) to 5.0V output at 1A load current for automotive, industrial, portable computers, battery chargers, and distributed power systems. This board was designed for wide input voltage range applications where simplicity, small circuit size, and low component count are important as well as up to 1A of load current. The extremely low output voltage ripple ceramic capacitor not only demonstrates small size and low cost, but the advantage of current-mode control in step-down applications with a simple compensation network and a feedforward capacitor for more rugged stability and excellent transient response. Demonstration Circuit 423 is best used in 500kHz applications where the maximum duty cycle does not exceed 75% and the minimum steady state duty cycle remains above 25%. Duty cycles below 25% are capable, with the restriction of minimum on-time, the part may begin to skip pulses to effectively lower the overall minimum on-time.