DC355A demonstration boards is for evaluation of DC/DC step down regulators using the LT1959 constant frequency, high efficiency converter in SO-8 packages. A 4.5A switch is included on the die along with all the necessary oscillator, control and logic circuitry. High switching frequency allows a considerable reduction in the size of external components. The topology is current mode for fast transient response and good loop stability. A special high speed bipolar process and new design techniques achieve high efficiency at high switching frequency. Efficiency is maintained over a wide output current range and by utilizing a supply boost capacitor to saturate the power switch. Full cycle by cycle short circuit protection and thermal shutdown are provided. There is the optional function of shutdown or synchronization. The SO-8 package can be used for dynamic loads up to the full rated switch current.