The TPS51621 is a selectable dual or single-phase, fully compliant IMVP-6.5 step-down controller with integrated gate drivers. Advanced control features such as D-CAP+ architecture and OSR overshoot reduction provide a fast transient response and lowest output capacitance. The TPS51621 also supports single-phase operation for light loads. The full complement of IMVP-6.5 I/O is integrated into the TPS51621, including VR_TT, DPRSLPVR, PSI and output current monitoring (IMON). PSI is used to control the number of active phases. Transitioning into and out of dual-phase mode is exceptionally smooth.