The SP6652 is high efficiency, synchronous buck regulator ideal for portable applications using one Li-Ion cell, with up to 1A output current. The 1.2MHz switching frequency and PWM control loop are optimized for small value inductor and ceramic output capacitor, for space constrained portable designs. At light load, the SP6652 can operate in either PFM mode for high efficiency, or PWM mode for constant frequency. In addition, the input voltage range of 2.7V to 5.5V; excellent transient response, output accuracy, and ability to transition into 100% duty cycle operation, further extending useful battery life, make the SP6652 a superior choice for a wide range of portable power applications. The output voltage is externally programmable down to 0.75V. A logic level shutdown control, external clock synchronization, and forced-PWM or automatic control inputs are provided. Other features include soft-start, over current protection and 140(C over-temperature shutdown. TYPICAL APPLICATION SCHEMATIC