The RT8249A/B/C 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 RT8249A/B has an oscillator output to driver the external charge pump application. The RT8249C 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 RT8249A/B/C automatically switches to the diode-emulation mode in light load applications. The RT8249A/B/C is available in the WQFN-20L 3x3 package.
- Notebook and Sub-Notebook Computers
- System Power Supplies
- 3-Cell and 4-Cell Li+ Battery-Powered Devices