The IM5200 is a synchronous buck controller mainly for widely varying input step-down regulator applications. The control method is based upon current mode control that enables maximum performance under transient conditions. The output voltage can be either programmed by the FB pin or configured by the I2C interface from 3.0V to 21V in 200mV per step. It operates as a Buck mode while the input voltage is sufficiently greater than the regulated output voltage and transitions to the bypass mode as the input voltage very approaches the output voltage. It also features an adjustable soft-start function and offers protection features including input UVLO, cycle-by-cycle current limit, output overload protection (OLP) or OVP and thermal shutdown. In addition, it features selectable Forced Continuous Conduction Mode (FCCM) or Discontinuous Conduction Mode (DCM) operation for light load. The IM5200 integrates an I2C compatible interface for bypass mode selecting, cable impedance compensation selecting, output voltage setting, etc. The IM5200 is available in compact QFN3x3-20.