Demonstration circuit 326C is a monolithic step-down DC/DC switching converter featuring the LT1766EFE. The board is optimized for 5V output at up to 1A load current and a steady state input voltage range of 6V to 60V. With its wide input voltage range, 1.5A internal power switch, 200kHz switching frequency and thermally enhanced package, the LT1766EFE is a very versatile and powerful IC for DC/DC converters that require compact space, high efficiency and tolerance to high input voltage transients. The LT1766EFE 200kHz switching frequency allows all of the components to be small, surface mount devices. Synchronization with an external clock of up to 700kHz is possible. The current-mode control topology creates fast transient response and good loop stability with a minimum number of external components. The low resistance internal power switch (0.2?) achieves high efficiencies of up to 90%. The SHDN pin can be used to program undervoltage lockout or place the part in micropower shutdown, reducing supply current to 25µA by driving the pin low. The LT1766EFE datasheet gives a complete of the part, operation and applications information. The datasheet must be read in conjunction with this Quick Start Guide for demonstration circuit 326C. In particular, the datasheet section on ‘Thermal Calculations’ is important for estimating whether a given application’s combination of input voltage, load current and frequency will cause the LT1766EFE to exceed it’s absolute maximum rated junction temperature. The LT1766EFE is assembled in a small 16-pin thermally enhanced package with exposed pad where proper board layout is essential for maximum thermal performance. See the datasheet section ‘Layout Considerations’.