Analog Devices Inc./Maxim Integrated

The LTC3850-2 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 LTC3850-2 features a precision 0.8V reference and a power good output indicator. A wide 4V to 30V 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 LTC3850-2 is identical to the LTC3850-1, except they have different pin assignments.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

The LTC3851A-1 is a high performance synchronous step-down switching regulator controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 750kHz.OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3851A-1 features a precision 0.8V reference and a power good indicator. A wide 4V to 38V (40V absolute maximum) input supply range encompasses most battery configurations and intermediate bus voltages.The TK/SS pin ramps the output voltage during start-up and shutdown with coincident or ratiometric tracking. 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 at light loads and allows the IC to be synchronized to an external clock. The LTC3851A-1 contains an improved PLL compared to the LTC3851-1.The LTC3851A-1 is identical to the LTC3851A except that the ILIMpin is replaced by PGOOD.FeaturesLTC3851Not Recommended For New DesignsLTC3851-1Not Recommended For New DesignsLTC3851AAdjustable Current LimitLTC3851A-1PGOOD OutputApplicationsAutomotive SystemsTelecom SystemsIndustrial EquipmentDistributed DC Power Systems

The LTC3851-1 is a high performance synchronous step-down switching regulator controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 750kHz.OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3851-1 features a precision 0.8V reference and a power good indicator. A wide 4V to 38V (40V absolute maximum) input supply range encompasses most battery configurations and intermediate bus voltages.The TK/SS pin ramps the output voltage during start-up and shutdown with coincident or ratiometric tracking. 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 at light loads and allows the IC to be synchronized to an external clock.The LTC3851-1 is identical to the LTC3851 except that the ILIMpin is replaced by PGOOD.FeaturesLTC3851Not Recommended For New DesignsLTC3851-1Not Recommended For New DesignsLTC3851AAdjustable Current LimitLTC3851A-1PGOOD OutputApplicationsAutomotive SystemsTelecom SystemsIndustrial EquipmentDistributed DC Power Systems

The LTC3851A-1 is a high performance synchronous step-down switching regulator controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 750kHz.OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3851A-1 features a precision 0.8V reference and a power good indicator. A wide 4V to 38V (40V absolute maximum) input supply range encompasses most battery configurations and intermediate bus voltages.The TK/SS pin ramps the output voltage during start-up and shutdown with coincident or ratiometric tracking. 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 at light loads and allows the IC to be synchronized to an external clock. The LTC3851A-1 contains an improved PLL compared to the LTC3851-1.The LTC3851A-1 is identical to the LTC3851A except that the ILIMpin is replaced by PGOOD.FeaturesLTC3851Not Recommended For New DesignsLTC3851-1Not Recommended For New DesignsLTC3851AAdjustable Current LimitLTC3851A-1PGOOD OutputApplicationsAutomotive SystemsTelecom SystemsIndustrial EquipmentDistributed DC Power Systems

The LTC3852 is a constant frequency, current mode step-down DC/DC controller which can be powered by an on-board charge pump. Input supplies as low as 2.7V, when doubled by the charge pump, provide 5V to the LTC3852’s control logic and gate drives, supporting a wide selection of logic-level N-channel power MOSFETs.The constant-frequency current mode architecture allows for a phase-lockable fixed frequency of up to 750kHz. The RUN pin provides a precision enable threshold while the TRACK/SS pin combines tracking and adjustable soft-start features.The MODE/PLLIN pin selects among Burst Mode®operation, pulse-skipping mode, and continuous current mode. Current foldback limits MOSFET power dissipation during short-circuit conditions. Reverse current and current foldback functions are disabled during soft-start. A power good output pin indicates when the output is within ±10% of its designed set point.ApplicationsGeneral Purpose 3.3V SystemsLithium-Ion Powered DevicesDistributed DC Power Systems

The LTC3854 is a high performance synchronous stepdown switching DC/DC controller that drives an all N-channel synchronous power MOSFET stage.The LTC3854 features a 400kHz constant frequency current mode architecture. The LTC3854 operates from a 4.5V to 38V (40V absolute maximum) input voltage range and regulates the output voltage from 0.8V to 5.5V.The RUN/SS pin provides both soft-start and enable features. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. Current foldback limits MOSFET dissipation during short circuit conditions. Current foldback functions are disabled during soft-start.The LTC3854 has a minimum on-time at 75ns, making it well suited for high step-down ratios. The strong onboard MOSFET drivers allow the use of high power external MOSFETs to produce output currents up to 20A.ApplicationsAutomotive SystemsTelecom SystemsIndustrial EquipmentDistributed DC Power Systems

The LTC3855 is a dual PolyPhase®current mode synchronous step-down switching regulator controller that drives all N-channel power MOSFET stages. It includes a high speed differential remote sense amplifier. The maximum current sense voltage is programmable for either 30mV, 50mV or 75mV, allowing the use of either the inductor DCR or a discrete sense resistor as the sensing element.The LTC3855 features a precision 0.6V reference and can produce output voltages up to 12.5V. A wide 4.5V to 38V input supply range encompasses most intermediate bus voltages and battery chemistries. Power loss and supply noise are minimized by operating the two controller output stages out of phase. Burst Mode®operation, continuous or pulse-skipping modes are supported.The LTC3855 can be configured for up to 12-phase operation, has DCR temperature compensation, two power good signals and two current limit set pins. The LTC3855 is available in low profile 40-pin 6mm × 6mm QFN and 38-lead exposed pad FE packages.ApplicationsComputer SystemsTelecom SystemsIndustrial and Medical InstrumentsDC Power Distribution Systems