Highly efficient monolithic synchronous step-down DC-DC converters

Now stocked by Digi-Key, Intersil's ISL78233 and ISL78234 are highly-efficient, monolithic, synchronous step-down DC-DC converters that can deliver 3A (ISL78233), 4A (ISL78234), and 5A (ISL7835) of continuous output current from a 2.7V to 5.5V input supply. The devices use current-mode control architecture to deliver a very low duty cycle operation at high frequency with fast transient response and exceptional loop stability. The ISL78233 and ISL78234 integrate a very low ON-resistance P-channel (35mohm) high-side FET and N-channel (11mohm) low-side FET to maximize efficiency and minimize external component count. The 100% duty-cycle operation allows less than 200mV dropout voltage at 4A output current. The operation frequency of the pulse width modulator (PWM) is adjustable from 500kHz to 4MHz. The default switching frequency of 2MHz is set by connecting the FS pin high. The ISL78233, ISL78234, and ISL78235 can be configured for discontinuous or forced continuous operation at light load. Forced continuous operation reduces noise and RF interference, while discontinuous mode provides higher efficiency by reducing switching losses at light loads.