RT9907

Description

The RT9907 is a three channel power-supply solution for digital still cameras and other battery-powered devices. It integrates an asynchronous step-up and two synchronous step-down DC-DC converters. The RT9907 is targeted for applications that use two AA cells or a single lithium-ion battery.
The three DC-DC converters (CH1, CH2, CH3) accept input voltage from 1.5V to 5.5V. Each DC-DC converter has better transient response and excellent stability by providing current-mode control and external compensation network. With built-in Internal MOSFET and up to 1.4MHz operating frequency, the RT9907 allows minimum BOM cost and PCB area.
The step-down DC-DC converters (CH2, CH3) can regulate output voltage as low as 0.8V. Three operational modes are available: PWM, PSM, Low-Dropout modes. At PWM mode, Internal synchronous rectifier with low R_DS(ON) dramatically reduces conduction loss and achieve 94% efficiency. It enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper P-MOSFET. No external Schottky diode is required in practical application.
Each DC-DC converter has independent enable input and soft-start function allowing versatile power sequence combination. Complete protection functions are implemented such as short circuit, over-voltage protection.
The RT9907 is available in small VQFN-24L 4x4 package.