The MAX639/MAX640/MAX653EPA step-down switching regulators provide high efficiency over a wide range of load currents, delivering up to 225mA. A current-limiting pulse-frequency-modulated (PFM) control scheme gives the devices the benefits of pulse-width-modulated (PWM) converters (high efficiency at heavy loads), while using only 10μA of supply current (vs. 2mA to 10mA for PWM converters). The result is high efficiency over a wide range of loads. The MAX639/MAX640/MAX653EPA input range is 4V to 11.5V, and the devices provide lower preset output voltages of 5V, 3.3V, and 3V, respectively. Or, the output can be user-adjusted to any voltage from 1.3V to the input voltage. The MAX639/MAX640/MAX653EPA have an internal 1A power MOSFET switch, making them ideal for minimum-component, low- and medium-power applications. For increased output drive capability, use the MAX649/MAX651/MAX652 step-down controllers, which drive an external P-channel FET to deliver up to 5W.
Feature
- High Efficiency for a Wide Range of Load Currents
- 10μA Quiescent Current
- Output Currents Up to 225mA
- Preset or Adjustable Output Voltage:
- 5.0V (MAX639)
- 3.3V (MAX640)
- 3.0V (MAX653)
- Low-Battery Detection Comparator
- Current-Limiting PFM Control Scheme
Applications
- 5V to 3.3V Conversion
- 9V Battery to 5V, 3.3V, or 3V Conversion
- High-Efficiency Linear Regulator Replacement
- Portable Instruments and Handy-Terminals