The MAX1763 is a high-efficiency, low-noise, step-up DC-DC converter intended for use in battery-powered wireless applications. This device maintains exceptionally low quiescent supply current (110A) despite its high 1MHz operating frequency. Small external components and a tiny package make this device an excellent choice for small hand-held applications that require the longest possible battery life. The MAX1763 uses a synchronous-rectified pulsewidth-modulation (PWM) boost topology to generate 2.5V to 5.5V outputs from a wide range of input sources, such as one to three alkaline or NiCd/NiMH cells or a single Lithium-ion (Li+) cell. Maxim's proprietary Idle ModeTM circuitry significantly improves efficiency at light load currents while smoothly transitioning to fixed-frequency PWM operation at higher load currents to maintain excellent full-load efficiency. Lownoise, forced-PWM mode is available for applications that require constant-frequency operation at all load currents. The MAX1763 may also be synchronized to an external clock to protect sensitive frequency bands in communications equipment.