DC/DC Converter, Linear Technology, LTC3538
DC/DC Converter Offers Extended Battery Run Time for Li-Ion Powered Handhelds
News Release from:
Linear Technology (UK) Limited
28 December 2007
Linear Technology has 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 2.4V to 5.5V and output range of 1.5V to 5.25 makes it ideal for single cell Li-Ion/Polymer applications. The LTC3538 provides a smooth continuous transfer through all of the operating modes, making it ideal 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 unique 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 combination of tiny externals and a 2mm x 3mm DFN package provide the tiny solution footprint required in handheld applications.
The LTC3538 includes two N-Channel MOSFETs and two P-Channel MOSFETs (0.17 Ohm and 0.20 Ohm, respectively) to deliver efficiencies of up to 96%. Burst Mode® operation requires only 35uA of quiescent current while shutdown current is less than 1uA to further extend battery run-time. Other features include soft-start, current limiting, thermal shutdown and output disconnect in shutdown.