Synchronous DC-DC Controller Draws Just 170 µA

The LTC3858/-1 is a low-quiescent-current, two-phase dual-output synchronous step-down DC-DC controller that draws only 170 µA with one output active and 300 µA when both outputs are active. With both outputs shut down, the LTC3858/-1 draws a mere 8 µA, which is ideal for automotive and notebook PC applications. A wide input supply range of 4 V to 38 V protects against automotive wide input voltage transients commonly found during load dump and cold crank conditions. In addition, it also covers a broad range of battery chemistries. Each output can be set from 0.8 V to 24 V at output currents up to 20 A with efficiency as high as 95%. The LTC3858/-1 is suitable for powering high-performance systems including navigation, audio, communications, CD/DVD players, and disk drives. It has powerful 1.1-O on-board MOSFET gate drivers and operates with an adjustable fixed frequency between 50 kHz and 900 kHz, or can be synchronized to an external clock from 75 kHz to 850 kHz using its phase-locked-loop. The LTC3858 is the fully featured version of the part with additional functions beyond the LTC3858-1, including a clock out, clock phase modulation, two separate power good signals, and adjustable current limit. The LTC3858 is offered in a 32-lead 5-mm x 5-mm QFN package, with the LTC3858-1 in 28-pin SSOP or 4-mm x 5-mm QFN-28 packages. Pricing starts at $4.47 in 1,000-piece quantities. For more information, visit www.linear.com. LINEAR TECHNOLOGY CORP., Milpitas, CA. (408) 432-1900.