5V to 3.3V Output, Synchronous, Step-Down Power Supply Controller

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, low-cost 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 available in 20-pin SSOP packages. For other fixed output voltages and package options, please consult the factory.

Applications

* Local 5V-to-3.3V DC-DC Conversion * Microprocessor Daughterboards * Power Supplies Up to 10A or More

* >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

* Fixed Output Voltages Available:

* 3.3V (Standard)

* 3.45V (High-Speed Pentium™)

* 3.6V (PowerPC™)