资 源 简 介
The RT9201 is a high-efficiency pulse-width-modulated(PWM) step-down DC-DC converter. Capable of delivering600mA output current over a wide input voltage rangefrom 2.5 to 5.5V, the RT9201 is ideally suited for portableelectronic devices that are powered from 1-cell Li-ionbattery or from other power sources within the range suchas cellular phones, PDAs and handy-terminals.Four operaTIonal modes are available: PWM, PSM, Low-Dropout and shut-down modes. Internal synchronousrecTIfier with low RDS(ON) dramaTIcally reduces conducTIonloss at PWM mode. No external Schottky diode isrequired in practical application. The RT9201 automaticallyturns off the synchronous rectifier while theinductor current is low and enters discontinuous PWMmode. This can increase efficiency at light load condition.The RT9201 enters PSM (pulse-skipping mode) atextremely light load condition. The equivalent switchingfrequency is reduced to increase the efficiency in PSM.The RT9201 enters Low-Dropout mode when normalPWM cannot provide regulated output voltage bycontinuously turning on the upper P-MOSFET. RT9201enters shut-down mode and consumes less than 0.1mAwhen EN pin is pulled low.The switching ripple is easily smoothed-out by smallpackage filtering elements due to a fixed operationfrequency of 800kHz. This along with small VDFN packageprovides small PCB area application. Other featuresinclude soft start, 0.8V internal reference voltage with1% accuracy, over temperature protection, and overcurrent protection.
