The PM6641 is a monolithic voltage regulator module specifically designed to supply DDR2/3 memory and chipset in ultra-mobile PC and real estate constrained portable systems. It integrates three independent, adjustable, constant frequency buck converters, a ±2 Apk low drop-out (LDO) linear regulator and a ±15 mA low noise buffered reference. Each regulator provides basic UV and OV protections, programmable soft-start and current limit and active soft-end. Pulse-skipping technique is performed to increase efficiency at very light load.