The UCC3941 family of low-input-voltage single-inductor boost-converters are optimized to operate from a single- or dual-alkaline cell, and step up to a 3.3-V, 5-V, or an adjustable output at 500 mW. The UCC3941 family also provides an auxiliary 9-V, 100-mW output, primarily for the gate drive supply, which can be used for applications requiring an auxiliary output such as a 5-V supply by linear regulating. The primary output starts up under full load at input voltages typically as low as 0.8 V, with a guaranteed maximum of 1 V, and operates down to 0.4 V once the converter is operating, maximizing battery utilization. Demanding applications such as pagers and personal digital assistants require high efficiency from several milliwatts to several hundred milliwatts, and the UCC3941 family accommodates these applications with > 80% typical efficiencies over the wide range of operation. The high-efficiency at low-output current is achieved by optimizing switching and conduction losses along with low-quiescent current. At higher output current the 0.25- charge switch, and the 0.4- synchronous rectifier, along with continuous-mode conduction, provide high efficiency. The wide input-voltage range on the UCC3941 family can accommodate other power sources such as NiCd and NiMH.