Converter extends battery run time in handheld applications.

Press Release Summary:



Supplied in 16-lead 3 x 5 mm DFN package or SSOP-16, LTC3534 synchronous buck-boost DC/DC converter delivers up to 500 mA output current to regulated output above, below, or equal to input using single inductor. It has 2.4-7 V input and 1.8-7 V output ranges as well as constant 1 MHz switching frequency, and inclusion of 2 N-channel and 2 P-channel MOSFETs deliver 94% efficiency. Burst Mode® operation requires 25 µA of quiescent current, and shutdown current is less than 1 µA.



Original Press Release:



LTC3605: 15V, 4MHz, Synchronous Step-Down Regulator Delivers 5A from a 4mm x 4mm QFN



LTC3534: 7V, 500mA Synchronous Buck-Boost DC/DC Converter Provides Extended Battery Run Time in Handheld Applications

Milpitas, California (Southern) - February 24, 2009

MILPITAS, CA - February 24, 2009 - Linear Technology announces the LTC3534, a 7V synchronous buck-boost converter that can delivers up to 500mA of output current to a regulated output above, below or equal to the input using a single inductor. The device's topology provides a continuous transfer through all operating modes making it ideal for three- or four- cell Alkaline/NiCad/NiMH or single cell lithium applications which must maintain a constant output voltage even as the battery voltage declines below the output. A typical application is alkaline cells with an input voltage range of 3.6V to 6.4V, powering a 5V output rail. In most cases this Buck-Boost DC/DC Converter can add up to 25% more battery run-time compared to a traditional SEPIC solution. The LTC3534's constant 1MHz switching frequency ensures low noise while minimizing the size of external components. The combination of tiny externals and a 3mm x 5mm DFN (or SSOP-16) provide a tiny solution footprint, typically required in handheld applications.

The LTC3534 includes two N-Channel MOSFETs and two P-Channel MOSFETs (215mOhm/275mOhm and 260mOhm, respectively) to deliver efficiencies of up to 94%. Burst Mode® operation requires only 25uA of quiescent current while shutdown current is less than 1uA, further extending battery run-time. If the application is noise sensitive, the PWM pin can also be configured to provide forced continuous operation to reduce noise and RF interference. Other features include soft-start, current limiting, thermal shutdown and output disconnect.

LTC3534EDD is available from stock in a 16-lead 3mm x 5mm DFN package, and the LTC3534EGN is available in a 16-lead SSOP package. Pricing for both versions is $3.15 each in 1,000 piece quantities. For more information, visit www.linear.com.

SUMMARY OF FEATURES: LTC3534
o Regulated Output with Input Voltages Above, Below or Equal to the Output
o 2.4V to 7V Input & 1.8V to 7V Output Voltage Ranges
o 5V VOUT at 500mA from 4 AA Cells
o Single Inductor
o Synchronous Rectification: Up to 94% Efficiency
o Burst Mode® Operation with 25uA IQ
o Output Disconnect in Shutdown
o 1MHz Switching Frequency
o <1uA Shutdown Current
o Small Thermally Enhanced 16-Lead (3mm x 5mm x 0.75mm) DFN & 16-Lead SSOP Packages

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