Low-Voltage, Step-Down DC-DC Converters in SOT23

The MAX1733/MAX1734 step-down DC-DC converters deliver over 250mA to outputs as low as 1.25V. These converters use a unique proprietary current-limited control scheme that achieves over 90% efficiency. These devices maintain extremely low quiescent supply current (40µA), and their high 1.2MHz (max) operating frequency permits small, low-cost external components. This combination of features makes the MAX1733/ MAX1734 excellent high-efficiency alternatives to linear regulators in space-constrained applications.

Internal synchronous rectification greatly improves efficiency and eliminates the external Schottky diode required in conventional step-down converters. Both devices also include internal digital soft-start to limit input current upon startup and reduce input capacitor requirements.

The MAX1733 provides an adjustable output voltage (1.25V to 2.0V). The MAX1734 provides factory-preset output voltages (see Selector Guide). Both are available in space-saving 5-pin SOT23 packages.

Applications

* Cell Phones * Computers: Desktop, Workstation, Server * Consumer Audio * Digital Still Cameras * Global Positioning Systems (GPS) * Palmtop Computers * POS Terminals * Wireless Data * Wireless Local Area Networks (WLANs)

* 250mA Guaranteed Output Current

* Synchronous Rectifier for Over 90% Efficiency

* Tiny 5-Pin SOT23 Package

* 40µA Quiescent Supply Current

* 0.01µA Logic-Controlled Shutdown

* Up to 1.2MHz Switching Frequency

* Fixed 1.8V or 1.5V Outputs (MAX1734)

* Adjustable Output Voltage (MAX1733)

* ±1.5% Initial Accuracy

* 2.7V to 5.5V Input Range

* Soft-Start Limits Startup Current