Milpitas, Calif.—Linear Technology's LTC3548 is a dual-output synchronous buck regulator that delivers up to 800 mA of continuous output current from one channel and up to 400 mA from the other for low-voltage (down to 0.6 V) DSPs and microcontrollers. The constant-frequency (2.25 MHz), current-mode device works from a 2.5- to 5.5-volt input, thus suiting it for use with single cell lithium-ion, multi-cell alkaline, or NiMH batteries.
The LTC3548 uses internal switches with an RDS(ON) of only 350 milliohms to deliver efficiencies as high as 95 percent. It also utilizes low-dropout 100 percent duty cycle operation (allowing output voltages up to VIN), further extending battery run-time. Its no-load quiescent current is 40 microamps, and less than 1 microamp in shutdown. The LTC3548 utilizes the company's Burst Mode operation, reducing gate-charge losses when the load current drops below the level required for continuous operation and providing optimum efficiency at light loads. If the application is noise-sensitive, the user can disable Burst Mode, replacing it with a lower noise pulse-skipping mode.
Other features include short-circuit protection, power-on reset output, and optional external synchronization capability. The device is stable with ceramic capacitors.
The LTC3548EDD is available in a 3-by-3 mm DFN-10 package and the LTC3548EMSE is in a thermally enhanced MSOP package. Both devices are available from stock, with pricing for both starting at $2.60 each for 1,000-piece quantities. A data sheet is available at www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1042,C1032,C1064,P10290,D7317
Linear Technology, 1-800-4-LINEAR, www.linear.com