New Industry Products

Linear Tech Announces Synchronous 400mA DC-DC Buck-Boost Converter

June 12, 2007 by Jeff Shepard

Linear Technology announced the LTC3522, a dual channel, 1MHz synchronous converter. One channel utilizes a synchronous buck-boost topology that can deliver up to 400mA of continuous output current with inputs above, equal, or below the output. In single cell Li-Ion applications requiring a 3.3V output, the buck-boost topology enables up to 25% longer battery run-time. The second channel is a synchronous buck regulator, which can deliver up to 200mA of continuous output current to voltages as low as 0.6V. This combination is suitable for powering applications such as DSPs and microcontrollers that require both a 3.3V I/O rail and a 0.6V to 1.8V rail for the core voltage. The LTC3522’s 1MHz switching frequency enables the use of tiny, low cost ceramic capacitors and inductors. Combined with its 3mm x 3mm QFN package, it is said to provide a compact solution footprint.

The LTC3522’s synchronous buck-boost topology on its 400mA channel enables it to regulate a constant output voltage when the input voltage is above, equal to or below the output, allowing it to use the entire stored energy of the Li-Ion battery. The LTC3522 utilizes automatic Burst Mode® operation, requiring only 25µA (both channels) of no load quiescent current. For applications that require very low noise, the Burst Mode function can be defeated and replaced with a continuous PWM mode. Shutdown current is less than 1uA, further extending battery run-time. Each channel has independent internal soft-start ensuring design flexibility. Other features include short-circuit protection, over-temperature protection, and a power good flags.

LTC3522EUD is available from stock in a 16-Lead QFN package. Pricing is $2.50 each for 1,000-piece quantities.