The LTC3809-1 is a no Rsense synchronous step-down controller packaged in a 3- by 3-mm DFN-10 (or MSOPE-10). The device's 550-kHz frequency and current-mode architecture with MOSFET VDS sensing eliminates the need for a current-sense resistor while delivering efficiencies as high as 95%. Designed by Linear Technology, the LTC3809-1 offers an input voltage range of 2.75 to 9.8 V, suiting it for single or dual Li-Ion or multi-cell NiMH/NiCd/Alkaline applications, as well as standard 3.3- and 5-V rails to operate in Burst Mode with only 100 ΜA of quiescent current, or in a pulse-skipping or forced continuous mode for low out put voltage ripple.
The LTC3809-1 offers a user-adjustable tracking/soft-start input that smoothly ramps the output voltage during startup. Other features include default internal soft-start circuitry, an auxiliary winding regulation and output over-voltage protection. Prices start at $2.50 each in 1000-piece quantities. For more information, visit www.linear.com