RT8249D

® RT8249D Dual-Channel Synchronous DC/DC Step-Down Controller with 5V/3.3V LDOs General Description The RT8249D is a dual-channel step-down, controller generating supply voltages for battery-powered systems. It includes two Pulse-Width Modulation (PWM) controllers adjustable from 2V to 5.5V, and two fixed 5V/3.3V linear regulators. Each linear regulator provides up to 100mA output current and 3.3V linear regulator provides 1% accuracy under 35mA. The RT8249D provides a mode selection pin, SKIPSEL, to select Diode-Emulation Mode (DEM) or Audio Skipping Mode (ASM). Other features include on-board power-up sequencing, a power-good output, internal soft-start, and soft-discharge output that prevents negative voltage during shutdown. A constant current ripple PWM control scheme operates without sense resistors and provides 100ns response to load transient. For maximizing power efficiency, the RT8249D automatically switches to the diode-emulation mode in light load applications. The RT8249D is available in the WQFN-20L 3x3 package. Features  Support Connected Standby Mode for Ultrabook  CCRCOT Control with 100ns Load Step Response  PWM Maximum Duty Ratio > 98%  5V to 25V Input Voltage Range  Dual Adjustable Output :  CH1 : 2V to 5.5V  CH2 : 2V to 4V  5V/3.3V LDOs with 100mA Output Current  1% Accuracy on 3.3V LDO Output  Oscillator Driving Output for Charge Pump Application  Internal Frequency Setting  500kHz/600kHz (CH1/CH2)  Internal Soft-Start and Soft-Discharge ...