Linear Adds 800mA, Synchronous Buck-Boost DC-DC Converter for Li-Ion Powered Handhelds

Linear Technology announced the LTC3538, a synchronous buck-boost converter that can deliver a regulated output voltage at up to 800mA of continuous current with an input voltage above, below or equal to the output. Its input range of 2.4 to 5.5V and output range of 1.5 to 5.25 makes it suitable for single cell Li-Ion/Polymer applications.

The LTC3538 is claimed to provide a smooth continuous transfer through all of the operating modes, making it suiatable for applications that must maintain a constant output voltage even as the battery voltage declines below the output. In Li-Ion/polymer-powered applications that require 3.3V outputs, such as miniature hard disk drives and DSP I/O power, this buck-boost design provides over 25% more battery run-time. The LTC3538’s constant 1MHz switching frequency ensures low noise while minimizing external component size.

The LTC3538 includes two N-Channel MOSFETs and two P-Channel MOSFETs (0.17 and 0.20Ω, respectively) to deliver efficiencies of up to 96%. Burst Mode® operation requires only 35uA of quiescent current while shutdown current is less than 1µA to further extend battery run-time. Other features include soft-start, current limiting, thermal shutdown and output disconnect in shutdown.

LTC3538EDCB is available from stock in a 2mm x 3mm 8-lead DFN package. Pricing is $2.65 each in 1,000 piece quantities.