资 源 简 介
The RT9907 is a three channel power-supply soluTIon fordigital sTIll cameras and other battery-powered devices. Itintegrates an asynchronous step-up and two synchronousstep-down DC-DC converters. The RT9907 is targeted forapplicaTIons that use two AA cells or a single lithium-ionbattery.The three DC-DC converters (CH1, CH2, CH3) accept inputvoltage from 1.5V to 5.5V. Each DC-DC converter hasbetter transient response and excellent stability byproviding current-mode control and external compensaTIonnetwork. With built-in Internal MOSFET and up to 1.4MHzoperating frequency, the RT9907 allows minimum BOMcost and PCB area.The step-down DC-DC converters (CH2, CH3) can regulateoutput voltage as low as 0.8V. Three operational modesare available: PWM, PSM, Low-Dropout modes. At PWMmode, Internal synchronous rectifier with low RDS(ON)dramatically reduces conduction loss and achieve 94%efficiency. It enters Low-Dropout mode when normal PWMcannot provide regulated output voltage by continuouslyturning on the upper P-MOSFET. No external Schottkydiode is required in practical application.Each DC-DC converter has independent enable input andsoft-start function allowing versatile power sequencecombination. Complete protection functions areimplemented such as short circuit, over-voltage protection.The RT9907 is available in small VQFN-24L 4x4 package.
