The MP21148 is a monolithic, step-down, switch-mode converter with built-in, internal power MOSFETs. It can achieve 1A of continuous output current from a 2.3V-to-5.5V input voltage with excellent load and line regulation. The output voltage can be regulated as low as 0.6V. The constant-on-time control scheme in forced CCM provides a fast transient response, low output voltage ripple, and eases loop stabilization. Fault protections include cycle-by-cycle current limiting and thermal shutdown. The MP21148 is available in an ultra-small QFN-6 (1.0mmx1.5mm) package and requires a minimal number of readily available, standard, external components. The MP21148 is ideal for a wide range of applications including high-performance DSPs, wireless power, portable and mobile devices, and other low-power systems.