The LTC3850 is a high performance dual synchronous step-down switching regulator controller that drives all N-channel power MOSFET stages. A constant-frequency current mode architecture allows a phase-lockable frequency of up to 780kHz. Power loss and supply noise are minimized by operating the two controller output stages out of phase.OPTI-LOOP®compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3850 features a precision 0.8V reference and a power good output indicator. A wide 4V to 24V (28V maximum/30V for LTC3850I) input supply range encompasses most battery chemistries and intermediate bus voltages.Independent TK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The MODE/PLLIN pin selects among Burst Mode®operation, pulse-skipping mode, or continuous inductor current mode and allows the IC to be synchronized to an external clock.The LTC3850 is available in low profile 28-pin 4mm × 4mm, 4mm × 5mm QFN and narrow SSOP packages.FeaturesLTC3850SSOP-28 and QFN-28 PackagesLTC3850-1ILIM function replaced with an EXTVCC function, SSOP-28 package onlyLTC3850-2The LTC3850-2 is identical to the LTC3850-1 SSOP-28, except they have different pin-outsApplicationsNotebook and Palmtop ComputersPortable InstrumentsBattery-Operated Digital DevicesDC Power Distribution Systems