RT8249C Chipset

RT8249C(Dual-Channel Synchronous DC/DC Step-Down Controller with 5V/3.3V LDOs)

Introduction

The RT8249C 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 RT8249C provi-des 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 RT8249C automatically switches to the diode-emulation mode in light load applications.

The RT8249C is available in the WQFN-20L 3×3 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
• 2V to 5.5V Output Voltage Range
• 5V/3.3V LDOs with 100mA Output Current
• 1% Accuracy on 3.3V LDO Output
• Oscillator Driving Output for Charge Pump

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