The TMI3411U is a high efficiency 1.2MHz, Advanced Constant-on-time (COT) control mode synchronous step-down Buck converter capable of delivering up to 2A current with 2.5V to 5.5V input voltage range. The device is ideal for portable equipment requiring output current up to 2A from single-cell Lithium-ion batteries or other input source and the output voltage can be regulated as low as 0.45V. The TMI3411U also can run at 100% duty cycle for low dropout operation, extending battery life in portable systems while light load operation provides very low output ripple for noise sensitive applications. It adopts the COT architecture to achieve fast transient responses for high voltage step down applications. TMI3411U requires a minimum number of readily available standard external components and is available in a 5-pin SOT23-5 ROHS compliant package. This device offers PFM Mode switching control at light load condition, which allows a high efficiency over the wider range of the load.