Analog Devices

The LTC3869 is a high performance dual synchronous step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 780kHz. Power loss and noise due to the ESR of the input capacitors 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. A wide 4V to 38V input supply range encompasses most battery chemistries. Independent TK/SS pins for each controller ramp the output voltage 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 LTC3869 is available in low profile 4mm × 4mm and 4mm × 5mm QFN packages. The LTC3869-2 is available in an SSOP-28 package. The LTC3869 is pin-compatible with the LTC3850.ApplicationsServer SystemsTelecom SystemsIndustrial and Medical InstrumentsHigh Power Battery-Operated DevicesDC Power Distribution Systems

The LTC3870-1 is a PolyPhase®step-down slave controller specially designed for multiphase operation with LTC's digital power system management DC/DC controllers. It provides a small and cost effective solution for supplying very large currents by cascading it with a LTC3887-1 controller. A peak current mode architecture provides the LTC3870-1 with excellent current sharing from phase to phase and from chip to chip.Coherently working with the LTC3887-1, the LTC3870-1 does not require additional I2C addresses, and it supports all programmable features as well as fault protection. The constant switching frequency can be synchronized to an external clock from the LTC3887-1 over a range of 100kHz to 1MHz.Onboard MOSFET Gate DriversPackageLTC3870Yes4x5 QFN-28LTC3870-1No – Works with DrMOS and Power Blocks4x4 QFN-24ApplicationsHigh Power Distributed Power SystemsTelecom SystemsIndustrial Applications

The LTC3871/LTC3871-1 is a high performance bidirectional buck or boost switching regulator controller that operates in either buck or boost mode on demand. It regulates in buck mode from VHIGH-to-VLOWand boost mode from VLOW-to-VHIGHdepending on a control signal, making it ideal for 48V/12V automotive dual battery systems. An accurate current programming loop regulates the maximum current that can be delivered in either direction. The LTC3871/LTC3871-1 allows both batteries to supply energy to the load simultaneously by converting energy from one battery to the other.Its proprietary constant-frequency current mode architecture enhances the signal-to-noise ratio enabling low noise operation and provides excellent current matching between phases. Additional features include discontinuous or continuous mode of operation, OV/UV monitors, independent loop compensation for buck and boost operation, accurate output current monitoring and overcurrent protection. The LTC3871 and LTC3871-1 have different current limit foldback characteristics.ApplicationsAutomotive 48V/12V Dual Battery SystemsBackup Power Systems

The LTC3872-1 is a constant frequency current mode boost DC/DC controller that drives an N-channel power MOSFET and requires very few external components. The No RSENSE™architecture eliminates the need for a sense resistor, improves efficiency and saves board space.The LTC3872-1 provides excellent AC and DC load and line regulation with ±1.5% output voltage accuracy. It incorporates an undervoltage lockout feature that shuts down the device when the input voltage falls below 2.3V.LTC3872-1 has the same functionality as the standard LTC3872 except that it has no frequency foldback in current limit.High switching frequency of 550kHz allows the use of a small inductor. The LTC3872-1 is available in an 8-lead low profile (1mm) ThinSOT™package and 8-pin 2mm × 3mm DFN package.LTC3872LTC3872-1Frequency Foldback In Current LimitYesNoApplicationsTelecom Power Supplies42V Automotive Systems24V Industrial ControlsIP Phone Power Supplies

The LTC3873-5 is a constant frequency current mode controller for boost, flyback or SEPIC DC/DC converters designed to drive an N-channel MOSFET for high input and output voltage converter applications.The LTC3873-5 provides ±1.5% output voltage accuracy and consumes only 300μA quiescent current during normal operation and only 50μA during micropower start-up. Using a 9.3V internal shunt regulator, the LTC3873-5 can be powered from a high input voltage through a resistor or it can be powered directly from a low impedance DC voltage of 9V or less. Soft-start can be programmed using an external capacitor.The LTC3873-5 is available in 8-lead ThinSOT and 2mm × 3mm DFN packages.LTC3873LTC3873-5VCCUV+8.4V3.9VVCCUV–4V2.9VApplicationsTelecom Power SuppliesAutomotive Power SuppliesPoE Applications

The LTC3874-1 is a dual PolyPhase®current mode synchronous step-down slave controller. It enables high current, multiphase applications when paired with a companion master controller by extending the phase count. Compatible master controllers include the LTC3884-1, LTC3774, LTC3875, LTC3877 and LTC3866. The LTC3874-1 employs a unique architecture that enhances the signal-to-noise ratio of the current sense signal, allowing the use of submilliohm DC resistance power inductors to maximize efficiency while reducing switching jitter. Its peak current mode architecture allows for accurate phase-to-phase current sharing even for dynamic loads.Effectively working with a master controller, the LTC3874-1 supports all the programmable features as well as fault protection.ApplicationsHigh Current Distributed Power SystemsTelecom, Datacom and Storage SystemsIntelligent Energy Efficient Power Regulation

The LTC3875 is a dual output current mode synchronous step-down DC/DC controller that drives all N-channel power MOSFET stages. It employs a unique architecture that enhances the signal-to-noise ratio of the current sense signal, allowing the use of very low DC resistance (DCR) power inductors to maximize efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications with current mode control.The LTC3875 features two high speed differential amplifiers which can be used to compensate for the voltage drop from the LTC3875 to the load. Its DCR temperature compensated adjustable over current trip points from 10mV to 30mV limits the maximum output current precisely over temperature.A unique thermal balancing function adjusts per phase current to minimize the thermal stress for multichip single output applications. The LTC3875 is available in the 40- lead 6mm × 6mm (0.5mm pitch) and 40-lead 5mm × 5mm (0.4mm pitch) QFN packages.APPLICATIONSServers and InstrumentsTelecom SystemsDC Power Distribution Systems

The LTC3876 is a complete DDR power solution, compatible with DDR1, DDR2, DDR3 and future DDRX lower voltage standards. The LTC3876 includes VDDQ and VTT DC/DC controllers and a precision linear VTT reference. A differential output sense amplifier and precision internal reference combine to offer an accurate VDDQ supply. The VTT controller tracks the precision VTTR linear reference with less than 20mV total DC error. The precision VTTR reference maintains 1.2% regulation accuracy tracking onehalf VDDQ over temperature for a ±50mA reference load.The LTC3876 allows operation from 4.5V to 38V maximum at the input. The VDDQ output can range from 1.0V to 2.5V, with a corresponding VTT and VTTR output range of 0.5V to 1.25V. Voltage tracking soft-start, PGOOD and fault protection features are provided.ApplicationsMotherboard MemoryServers

The LTC3877 is a VID-programmable, constant frequency current mode step-down controller using an advanced and proprietary architecture. This new architecture enhances the signal-to-noise ratio of the current sense signal, allowing the use of very low DC resistance power inductors to maximize efficiency in high current applications. This feature also dramatically reduces the current sensing error, so that current sharing is greatly improved in multi-phase low DCR applications. In addition, the controller achieves a minimum on-time of just 40ns, permitting the use of high switching frequency at high step-down ratios.The LTC3877 features dual high speed remote sense differential amplifiers, programmable current sense limits and DCR temperature compensation to limit the maximum output current precisely over temperature. The LTC3877 also features a precise 0.6V reference with guaranteed accuracy of ±0.5%. The LTC3877 is available in a low profile 44-lead 7mm × 7mm QFN package.ApplicationsFPGAs and Processor PowerServers and Computing

The LTC3878 is a synchronous step-down switching DC/DC controller optimized for high switching frequency and fast transient response. The constant on-time valley current mode architecture allows for a wide input range, including very low duty factor operation. No external sense resistor or slope compensation is required. The LTC3878 is pin compatible with the LTC1778 in applications that do not use EXTVCCwhile offering better efficiency. Consult with the factory to verify compatibility.Operating frequency is set by an external resistor and compensated for variations in VINto offer excellent line stability. Discontinuous mode operation provides high efficiency during light load conditions. A forced continuous control pin allows the user to reduce noise and RF interference. Safety features include output overvoltage protection and programmable current limit with foldback. Soft-start capability for supply sequencing is accomplished through an external timing capacitor. The current limit is user programmable.The LTC3878 allows operation from 4V to 38V at the input and from 0.8V to 90% VINat the output. The LTC3878 is available in a small 16-pin narrow SSOP package.ApplicationsDistributed Power SystemsEmbedded ComputingCommunications Infrastructure