5V/3.3V or Adjustable, 100% Duty Cycle, High-Efficiency, Step-Down DC-DC Controllers

The MAX1626/MAX1627 step-down DC-DC controllers operate over a 2.6V to 16.5V input voltage range. The controllers deliver load current from 1mA to more than 2A. The MAX1626 has pin-selectable 3.3V and 5V outputs. The MAX1627 supports adjustable outputs from 1.3V to 16V.

A unique current-limited, pulse-frequency-modulation (PFM) control scheme operates up to 100% duty cycle, resulting in very low dropout voltage. This control scheme eliminates minimum load requirements and reduces supply current under light loads to 90µA (versus 2mA to 10mA for common pulse-width modulation controllers).

The devices are available in a 8-pin SOIC package (-40°C to +85°C) and dice (0°C to +70°C).

Applications

* 5V to 3.3V Green PC Applications * Battery-Powered Applications * Handheld Computers * High-Efficiency Step-Down Regulation * Low-Cost Notebook Computer Supplies * Minimum Component DC-DC Converters * PCMCIA Power Supplies * PDAs and Other Handheld Devices * Portable Terminals

* Reduce External Components and Total Cost

* 300KHz PWM Switching Reduces Component Size

* Tiny Surface-Mount Inductor

* Reduce Power Dissipation

* > 90% Efficiency from 3mA to 2A Loads

* Low Dropout Voltage

* 100% Maximum Duty Cycle

* Reduce Number of DC-DC Controllers to Stock

* Wide 2.6V to 16.5V Input Voltage Options

* Selectable 3.3V and 5V or Adjustable 1.3V to 16V Output Voltage Options

* Reduce System Power Consumption

* 90µA Max Quiescent Current

* 1µA Max Shutdown Current

* Operates Reliably in Adverse Environment

* Soft-Start Limits Startup Current

* Current-Limited Control Scheme

* Increase Design Flexibility

* External P-Channel MOSFET Allows Output Power of > 12.5W