Low Voltage, High Efficiency Step-Down DC/DC Converter

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The LTC1626 is a monolithic, low voltage, step-down current mode DC/DC converter featuring Burst Mode™ operation at low output current.

The input supply voltage range of 2.5V to 6V makes the LTC1626 ideal for single cell Li-Ion and 3- or 4-cell NiCd/NiMH applications. A built-in 0.32Ω switch (VIN = 4.5V) allows up to 0.6A of output current.

The LTC1626 incorporates automatic power saving Burst Mode operation to reduce gate charge losses when the load current drops below the level required for continuous operation. With no load, the converter draws only 165µA. In shutdown, it draws a mere 0.5µA—making it ideal for current sensitive applications.

The inductor current is user-programmable via an external current sense resistor. In dropout, the internal P-channel MOSFET switch is turned on continuously, maximizing battery life.

Applications

* Single Cell Li-Ion Step-Down Converters

* 3- or 4-Cell NiMH Step-Down Converters

* Cellular Telephones

* 5V to 3.3V Conversion

* 3.3V to 2.5V Conversion

* Inverting Converters

* Portable Instruments

* Wide Input Supply Voltage Range: 2.5V to 6V

* High Efficiency: Up to 95%

* Low RDS(ON) Internal Switch: 0.32Ω (VIN = 4.5V)

* Current Mode Operation for Excellent Line and Load Transient Response

* Short-Circuit Protected

* Low Dropout Operation: 100% Duty Cycle