The LTC3536 from Linear Technology is a synchronous buck-boost converter that delivers up to 1A of output current from a Li-ion and polymer source or 300mA from dual cell alkaline, NiCd, or NiMH battery sources. The converter's 1.8 to 5.5V input and output voltage range is claimed to achieve ±1% output with inputs above, below or equal to the regulated output. The latest generation single inductor buck-boost PWM topology which is incorporated in the converter is claimed to provide a continuous transition through all of the operating modes, making it suitable for noise-sensitive applications. The converter's switching frequency ranges from 300kHz to 2MHz and can be synchronised to a system clock, optimising the trade-off between efficiency and external component size, says the company. The converter includes two N- and P-channel MOSFETs with RDS(ON) of 0.06 and 0.08Ω, respectively. Burst mode operation enhances the efficiency at light loads and requires 28µA of quiescent current and shutdown current of less than 1µA. Other features include soft-start, short circuit protection, current limiting and thermal shutdown. The converter is available in thermally enhanced 10-lead 3x3mm DFN and 12-lead MSOP packages in both E and I grades.
