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Switching Regulator - Switching Regulators 
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MAX639
5V/3.3V/3V Adjustable, High-Efficiency, Low-IQ, Step-Down DC-DC Converters
Low Supply Current, High-Efficiency Over Wide Load Range
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Key Features
Applications/Uses
Parametric specs for Step-Down Switching Regulators
| VIN (V) (min) | 4 |
| VIN (V) (max) | 11.5 |
| VOUT1 (V) (min) | 1.3 |
| VOUT1 (V) (max) | 11.5 |
| IOUT1 (A) (max) | 0.225 |
| Switch Type | Internal |
| Preset VOUT (V) | 3 5 |
| Output Adjust. Method | Preset Resistor |
| Power Good Signal | Yes |
| # DC-DC Outputs | 1 |
| Package/Pins | PDIP/8 SOIC (N)/8 |
| Budgetary Price (See Notes) | 3.76 |
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Parameters
Parametric specs for Step-Down Switching Regulators
| VIN (V) (min) | 4 |
| VIN (V) (max) | 11.5 |
| VOUT1 (V) (min) | 1.3 |
| VOUT1 (V) (max) | 11.5 |
| IOUT1 (A) (max) | 0.225 |
| Switch Type | Internal |
| Preset VOUT (V) | 3 5 |
| Output Adjust. Method | Preset Resistor |
| Power Good Signal | Yes |
| # DC-DC Outputs | 1 |
| Package/Pins | PDIP/8 SOIC (N)/8 |
| Budgetary Price (See Notes) | 3.76 |
Key Features
- 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/Uses
- 5V to 3.3V Conversion
- 9V Battery to 5V, 3.3V, or 3V Conversion
- High-Efficiency Linear Regulator Replacement
- Portable Instruments and Handy-Terminals
Description
The MAX639/MAX640/MAX653 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/MAX653 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/MAX653 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.
The MAX639/MAX640/MAX653 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/MAX653 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.
Technical Docs
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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