RT8204B

RT8204B Single Synchronous Buck with LDO Controller General Description The RT8204B PWM controller provides the high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high voltage batteries to generate low voltage CPU core, I/O, and chipset RAM supplies in notebook computers. The constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency. The RT8204B achieves high efficiency at a reduced cost by eliminating the current sense resistor found in traditional current mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous rectifier MOSFETs. The buck conversion allows this device to directly step down high voltage batteries for the highest possible efficiency. The RT8204B is intended for CPU core, chipset, DRAM, or other low voltage supplies as low as 0.75V. A built-in LDO controller can drive an external N-MOSFET to provide a second output voltage from PWM output or other power source. The RT8204B can provide adjustable voltage down to 0.75V and maximum output voltage is depended on the selected MOSFET. The internal 0.75V reference voltage with ±1.5% accuracy provides tight regulation for the output voltage. The independent enable control, open drain power good indicator, under voltage protection and soft start make RT8204B to power the system friendly. The...