7V, 500mA Synchronous Buck-Boost DC/DC Converter

The LTC3534 is a wide VIN range, highly efficient, fixed frequency, buck-boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for multi-cell Alkaline/NiMH or single Lithium-Ion/Polymer applications where the output voltage is within the battery voltage range.

The LTC3534 offers extended VIN and VOUT ranges of 2.4V to 7V and 1.8V to 7V, respectively. Quiescent current is only 25μA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the PWM pin low. If the PWM pin is driven high then fixed frequency switching is enabled.

Other features include fixed 1MHz operating frequency, a <1μA shutdown, short-circuit protection, programmable soft-start, current limit and thermal overload protection. The LTC3534 is available in the thermally enhanced 16-lead (3mm × 5mm) DFN and 16-lead GN packages.

Applications

* Medical Instruments

* Portable Barcode Readers

* Portable Inventory Terminals

* USB to 5V Supply

* Handheld GPS

* Regulated Output with Input Voltages Above, Below or Equal to the Output

* 2.4V to 7V VIN and 1.8V to 7V VOUT Ranges

* 5V VOUT at 500mA from 4 AA Cells

* Single Inductor

* Synchronous Rectification: Up to 94% Efficiency

* Burst Mode® Operation with 25μA IQ

* Output Disconnect in Shutdown

* 1MHz Switching Frequency

* <1μA Shutdown Current

* Small Thermally Enhanced 16-Lead (5mm × 3mm × 0.75mm) DFN and 16-Lead GN Packages