Analog Devices Inc./Maxim Integrated

The LTC3703 is a synchronous step-down switching regulator controller that can directly step-down voltages from up to 100V, making it ideal for telecom and automotive applications. The LTC3703 drives external N-channel MOSFETs using a constant frequency (up to 600kHz), voltage mode architecture.A precise internal reference provides 1% DC accuracy. A high bandwidth error amplifier and patented line feed forward compensation provide very fast line and load transient response. Strong 1Ω gate drivers allow the LTC3703 to drive multiple MOSFETs for higher current applications. The operating frequency is user programmable from 100kHz to 600kHz and can also be synchronized to an external clock for noise-sensitive applications. Current limit is programmable with an external resistor and utilizes the voltage drop across the synchronous MOSFET to eliminate the need for a current sense resistor. For applications requiring up to 60V operation with logiclevel MOSFETS, refer to the LTC3703-5 data sheet.LTC3703-5LTC3703Maximum VIN60V100VMOSFET Gate Drive4.5V to 15V9.3V to 15VVCCUV+3.7V8.7VVCCUV-3.1V6.2VApplications48V Telecom and Base Station Power SuppliesNetworking Equipment, ServersAutomotive and Industrial Control

The LTC3703-5 is a synchronous step-down switching regulator controller that can directly step-down voltages from up to 60V, making it ideal for telecom and automotive applications. The LTC3703-5 drives external logic level N-channel MOSFETs using a constant frequency (up to 600kHz), voltage mode architecture.A precise internal reference provides 1% DC accuracy. A high bandwidth error amplifier and patented* line feed forward compensation provide very fast line and load transient response. Strong 1Ω gate drivers allow the LTC3703-5 to drive multiple MOSFETs for higher current applications. The operating frequency is user programmable from 100kHz to 600kHz and can also be synchronized to an external clock for noise-sensitive applications. Current limit is programmable with an external resistor and utilizes the voltage drop across the synchronous MOSFET to eliminate the need for a current sense resistor. For applications requiring up to 100V operation, refer to the LTC3703 data sheet.LTC3703-5LTC3703Maximum VIN60V100VMOSFET Gate Drive4.5V to 15V9.3V to 15VVCC UV+3.7V8.7VVCC UV–3.1V6.2VApplications48V Telecom and Base Station Power SuppliesNetworking Equipment, ServersAutomotive and Industrial Control

The LTC3705 is a controller for a 2-switch forward converter and includes on-chip bottom and top gate drivers that do not require external transformers. For secondary-side control, combine the LTC3705 with the LTC3706 PolyPhase®secondary-side synchronous forward controller to create a complete forward converter using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals across the isolation barrier through a tiny pulse transformer. The on-chip rectifier and the same pulse transformer provide gate drive bias power.Alternatively, the LTC3705 can be used as a standalone voltage mode controller in a primary-side control architecture with optoisolator feedback. Voltage feedforward provides excellent line regulation and transient response.ApplicationsIsolated 48V Telecommunication SystemsInternet Servers and RoutersDistributed Power Step-Down ConvertersAutomotive and Heavy Equipment

The LTC3707-SYNC is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows phase-lockable frequency of up to 300kHz. 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. The precision 0.8V reference and power good output indicator are compatible with future microprocessor generations, and a wide 4.5V to 28V (30V maximum) input supply range encompasses all battery chemistries.A RUN/SS pin for each controller provides both soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when overcurrent latchoff is disabled. Output overvoltage protection circuitry latches on the bottom MOSFET until VOUTreturns to normal. The FCB mode pin can select among Burst Mode, constant frequency mode and continuous inductor current mode or regulate a secondary winding. The IC includes a power good output pin that indicates when both outputs are within 7.5% of their designed set point.External SynchronizationLTC3707NoLTC3707-SYNCYesApplicationsNotebook and Palmtop Computers, PDAsTelecom SystemsPortable InstrumentsBattery-Operated Digital DevicesDC Power Distribution Systems

The LTC3708 is a dual, 2-phase synchronous step-down switching regulator with output voltage up/down tracking capability. The IC allows either coincident or ratiometric tracking. Multiple LTC3708s can be daisy-chained in applications requiring more than two voltages to be tracked. Power supply sequencing is accomplished using an external soft-start timing capacitor.The LTC3708 uses a constant on-time, valley current mode control architecture to deliver very low duty factors without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in input supply voltage. An internal phase-locked loop allows the IC to be synchronized to an external clock.Fault protection is provided by an output overvoltage comparator and an optional short-circuit shutdown timer. The regulator current limit level is user programmable. A wide supply range allows voltages as high as 36V to be stepped down to 0.6V output.ApplicationsNotebook and Palmtop Computers, PDAsDigital Signal ProcessorsNetwork Servers

The LTC3709 is a single output, dual phase, synchronous step-down switching regulator. The controller uses a constant on-time, valley current control architecture to deliver very low duty cycles without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in input supply voltage. An internal phase-locked loop allows the LTC3709 to be synchronized to an external clock.A TRACK pin is provided for tracking or sequencing the output voltage among several LTC3709 chips or an LTC3709 and other DC/DC regulators. Soft-start is accomplished using an external timing capacitor.Fault protection is provided by an output overvoltage comparator and an optional short-circuit shutdown timer. The current limit level is user programmable. A wide supply range allows voltages as high as 31V to step down to 0.6V.Protected by U.S. Patents, including 5481178, 6476589, 6144194, 5847554, 6177678, 6304066, 6580258, 6674274, 6462525, 6593724.ApplicationsNotebook ComputersPower Supply for DSP, ASIC, Graphic Processors