Dual-Output DC-DC Controller Draws Only 170 µA

Drawing just 170 µA with one output active and 300 µA with both outputs active, the LTC3868/-1 is a low quiescent-current, two-phase synchronous step-down DC-DC controller that is well suited for battery-powered applications. With both outputs shut down, the LTC3868/-1 draws only 8 µA. The controller has an input supply range of 4 V to 24 V; each output can be set from 0.8 V to 14 V at output currents up to 20 A. With efficiency as high as 95%, a LTC3868/-1-based DC-DC converter is a candidate for powering industrial and medical devices, along with portable instruments, notebook and netbook computers. Operation is at a user-adjustable fixed frequency between 50 kHz and 900 kHz. The controller can be synchronized to an external clock from 75 kHz to 850 kHz using its phase-locked loop (PLL). Users can select from continuous operation, pulse skipping, and low-ripple burst mode operation during light loads. The LTC3868/-1 also features tight ±1.5% reference voltage accuracy over a -40ºC to 85ºC operating temperature range. The full-featured LTC3868 adds clock out, phase modulation, two power-good outputs and adjustable current limit to the basic -1 model. The LTC3868 is offered in a 32-lead, 5-mm-x-5-mm QFN package and the LTC3868-1 in 28-pin SSOP or 4-mm-x-5-mm QFN-28 packages. Pricing starts at $2.59 each in lots of 1000. LINEAR TECHNOLOGY CORP., Milpitas, CA. (408) 432-1900.