The TMI3257I is a high efficiency, 800kHz switching frequency, Constant on-Time (COT) control mode synchronous step-down DC-DC converter capable of delivering up to 2A current with small size SOT563 package. TMI3257I integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. Low output voltage ripple and small external inductor and capacitor size are achieved with 800kHz switching frequency. It adopts the COT architecture to achieve fast transient responses for high voltage step down applications. The TMI3257I requires a minimum number of readily available standard external components and is available in a 6-pin small size SOT563 RoHS compliant package.