MAX767

19-0224; Rev 2; 8/94 ual Man et t i he nK atio Data S u l a Ev llows Fo 5V-to-3.3V, Synchronous, Step-Down Power-Supply Controller ____________________________Features o o o o o o o o o >90% Efficiency 700µA Quiescent Supply Current 120µA Standby Supply Current 4.5V-to-5.5V Input Range Low-Cost Application Circuit All N-Channel Switches Small External Components Tiny Shrink-Small-Outline Package (SSOP) Predesigned Applications: Standard 5V to 3.3V DC-DC Converters up to 10A High-Accuracy Pentium P54C VR-Spec Supply o Fixed Output Voltages Available: 3.3V (Standard) 3.45V (High-Speed Pentium™) 3.6V (PowerPC™) _______________General Description The MAX767 is a high-efficiency, synchronous buck controller IC dedicated to converting a fixed 5V supply into a tightly regulated 3.3V output. Two key features set this device apart from similar, low-voltage step-down switching regulators: high operating frequency and all N-channel construction in the application circuit. The 300kHz operating frequency results in very small, lowcost external surface-mount components. The inductor, at 3.3µH for 5A, is physically at least five times smaller than inductors found in competing solutions. All N-channel construction and synchronous rectification result in reduced cost and highest efficiency. Efficiency exceeds 90% over a wide range of loading, eliminating the need for heatsinking. Output capacitance requirements are low, reducing board space and cost. The MAX767 is a monolithic BiCMOS IC av...