Milpitas, Calif.—Linear Technology's LTC3822 is a 750-kHz step-down DC/DC controller that's suited for driving all n-channel MOSFETs in 20 amp applications. The synchronous device further improves efficiency by using MOSFET drain-to-source resistance for current-sensing, doing away with the sense resistor traditionally employed.
The LTC3822, working from a 2.75 to 4.5-volt input, is suited to point-of-load conversion from 3.3-volt portable devices powered by single lithium-ion batteries. It provides sufficient drive for up to 20-amp load current requirements, while touting tight line and load regulation as well as fast transient response by virtue of its current-mode topology. Designers can adjust the output from this low-dropout device (99 percent maximum duty cycle) from 0.6 volt to 99 percent of the input voltage. Internal soft-start circuitry guarantees controlled startup to minimize inrush current. The LTC3822 consumes just 340 microamps during normal operation and just 7.5 microamps in shutdown.
Click here for the product datasheet. The LTC3822 is offered in two packages: A 10-lead MSOP, and a smaller 3-by-3 mm DFN. It is rated for operation over -40 to +85°C. The chip is priced at $2.10 each in 1k quantities.
Linear Technology, 1-800-4LINEAR, www.linear.com