Date: 30/01/2009

Synchronous buck type DC/DC Converter with adjustable outputs

The LTC3569 from linear technology is a triple channel, high efficiency 3MHz synchronous buck regulator that delivers up 1.2A of continuous output current from one channel and 600mA from each of the other two channels. Using a constant frequency current mode architecture, the LTC3569 operates from an input voltage range of 2.5V to 5.5V, making it ideal for single-cell Li-Ion/polymer, or multicell alkaline/NiCad/NiMH applications. Each of the three output voltages are independently programmable, by lowering the feedback voltage of each channel from 800mV to 425mV (in 25mV increments) by toggling the EN pin, enabling dynamic adjustment of each channel's output voltage. Additionally, each of the 600mA regulators can act as slave power stages to each other or to the 1.2A channel to support higher currents, thereby providing additional design flexibility.
The LTC3569's switching frequency can be programmed between 1MHz and 3MHz or set at 2.25MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands.
The LTC3569's internal synchronous switches offer efficiencies up to 95% while burst mode operation minimizes quiescent current to only 100uA (all three channels) in no-load conditions. For applications demanding the lowest possible noise, the LTC3569 can run in a pulse skipping mode to minimize output ripple. The LTC3569 offers a Power Good indicator and is synchronizable to an external clock (1.2MHz to 3MHz) other features include internal compensation, over-temperature and short circuit protection.

Package: LTC3569EUD: 3mm x 3mm QFN-20 package
LTC3569EFE: 16-lead TSSOP package.
Price: LTC3569EUD and LTC3569EFE start at $3.10 and $3.20 each respectively, in 1,000-piece quantities. Industrial grade versions, the LTC3569IUD and LTC3569IFE, are priced at $3.65 and $3.75 each respectively, in 1,000-piece quantities.
Availability: Now in volumes