G5603

Global Mixed-mode Technology Inc. G5603 High-Speed Step-Down Controller Features „ Ultra-High Efficiency „ No Current-Sense Resistor (Lossless ILIMIT) „ Quasi-PWM with 100ns Load-Step Response „ 1% VOUT Accuracy Over Line and Load „ 0.75V to 3.6V Adjustable Output Range „ 4.5V to 24V Battery Input Range „ Integrated Boost Diode „ OVP & UVP „ 1.7ms Soft-Start „ Drives Large Synchronous-Rectifier FETs „ Power-Good Indicator Applications „ Notebook Computers „ CPU Core Supply „ I/O Supply „ Chipset/RAM Supply as Low as 0.75V „ Networking Power Supply General Description G5603 uses constant on-time control scheme to handle wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency. The G5603 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by an ability to drive very large synchronous rectifier MOSFETs. Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size. The G5603 is intended for CPU core, chipset, DRAM, or other low-voltage supplies as low as 0.75V. The G5603 is available in TSSOP-14 、 TQFN3X3-16 and TQFN3.5X3.5-14 packa...