Analog Devices

The LTC3714 is a synchronous step-down switching regulator controller for CPU power. An output voltage between 0.6V and 1.75V is selected by a 5-bit code (Intel mobile VID specification). 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 VINand VOUT.Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling discontinuous mode when the main output is lightly loaded. Internal op amp allows programmable offsets to the output voltage during power saving modes.Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is user programmable. Wide supply range allows operation from 4V to 36V at the input.ApplicationsPower Supply for Mobile Pentium®Processors and Transmeta ProcessorsNotebook and Portable Computers

The LTC3716 is a 2-phase, VID programmable, synchronous step-down switching regulator controller that drives two N-channel external power MOSFET stages in a fixed frequency architecture. The 2-phase controller drives its two output stages out of phase at frequencies up to 300kHz to minimize the RMS ripple currents in both input and output capacitors. The 2-phase technique effectively multiplies the fundamental frequency by two, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.An operating mode select pin (FCB) can be used to regulate a secondary winding or select among three modes including BurstMode™operation for highest efficiency. An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required in high current applications.The RUN/SS pin provides soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the overcurrent latchoff is disabled. OPTI-LOOP compensation allows the transient response to be optimized for a wide range of output capacitors and ESR values.ApplicationsMobile Computer CPU Supply

The LTC3717 is a synchronous step-down switching regulator controller for double data rate (DDR) and Quad Data Rate™(QDR™) memory termination. The controller uses a 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 VIN.Forced continuous operation reduces noise and RF interference. Output voltage is internally set to half of VREF, which is user programmable.Fault protection is provided by an output overvoltage comparator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is symmetrical and user programmable. Wide supply range allows operation from 4V to 36V at the VCCinput.Von PinPackageLTC3717NoSSOP-16LTC3717-1YesQFN-32ApplicationsBus Termination: DDR and QDR Memory, SSTL, HSTL, ...Notebook Computers, Desktop ServersTracking Power Supply

The LTC3718 is a high current, high efficiency synchronous switching regulator controller for DDR and QDR™memory termination. It operates from an input as low as 1.5V and provides a regulated output voltage equal to (0.5)VIN. The controller uses a valley current control architecture to enable high frequency operation with very low on-times without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VINand VOUT. The LTC3718 uses a pair of standard 5V logic level N-channel external MOSFETs, eliminating the need for expensive P-channel or low threshold devices.Forced continuous operation reduces noise and RF interference. Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and an optional short-circuit timer. Soft-start capability for supply sequencing can be accomplished using an external timing capacitor. OPTI-LOOP®compensation allows the transient response to be optimized over a wide range of loads and output capacitors.ApplicationsBus Termination: DDR/QDR Memory, SSTL, HSTL,...Servers, RAID SystemsDistributed Power SystemsSynchronous Buck with General Purpose Boost

The LTC3719 is a 2-phase, VID programmable, synchronous step-down switching regulator controller that drives two N-channel external power MOSFET stages in a fixed frequency architecture. The 2-phase controller drives its two output stages out of phase at frequencies up to 300kHz to minimize the RMS ripple currents in both input and output capacitors. The 2-phase technique effectively multiplies the fundamental frequency by two, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.An operating mode select pin (FCB) can be used to select among three modes including Burst Mode®operation for highest efficiency. An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required in high current applications.The RUN/SS pin provides soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the overcurrent latchoff is disabled. OPTI-LOOP compensation allows the transient response to be optimized for a wide range of output capacitors and ESR values.ApplicationsServers and Workstations

The LTC3720 is a synchronous step-down switching regulator controller for CPU power. An output voltage between 1.05V and 1.825V is selected by a 5-bit code (Intel VRM8.5 VID specification). The controller uses a 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 VINand VOUT.Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling discontinuous mode operation when the main output is lightly loaded.Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is also user programmable. Wide supply range allows operation from 4V to 36V at the input.ApplicationsPower Supplies for Pentium®ProcessorsNotebook Computers and Servers

The LTC3721-1 push-pull PWM controller provides all of the control and protection functions necessary for compact and highly efficient, isolated power converters. High integration minimizes external component count, while preserving design flexibility.The robust push-pull output stages switch at half the oscillator frequency. Dead-time is independently programmed with an external resistor. A UVLO program input provides precise system turn-on and turn off voltages. The LTC3721-1 features peak current mode control with programmable slope compensation and leading edge blanking.The LTC3721-1 features extremely low operating and start-up currents and reliable short-circuit and overtemperature protection. The LTC3721-1 is offered in 16-pin SSOP and (4mm × 4mm) QFN packages.ApplicationsTelecommunications, Infrastructure Power SystemsDistributed Power ArchitecturesServer Power SuppliesHigh Density Power Modules

The LTC3722-1/LTC3722-2 phase-shift PWM controllers provide all of the control and protection functions necessary to implement a high efficiency, zero voltage switched (ZVS), full bridge power converter. Adaptive ZVS circuitry delays the turn-on signals for each MOSFET independent of internal and external component tolerances. Manual delay set mode enables secondary side control operation or direct control of switch turn-on delays.The LTC3722-1/LTC3722-2 feature adjustable synchronous rectifier timing for optimal efficiency. A UVLO program input provides accurate system turn-on and turn-off voltages. The LTC3722-1 features peak current mode control with programmable slope compensation and leading edge blanking, while the LTC3722-2 employs voltage mode control.The LTC3722-1/LTC3722-2 feature extremely low operating and start-up currents. Both devices include a full range of protection features and are available in the 24-pin surface mount GN package.ApplicationsTelecommunications, Infrastructure Power SystemsDistributed Power ArchitecturesServer Power Supplies

The LTC3723-1/LTC3723-2 synchronous push-pull PWM controllers provide all of the control and protection functions necessary for compact and highly efficient, isolated power converters. High integration minimizes external component count, while preserving design flexibility.The robust push-pull output stages switch at half the oscillator frequency. Dead-time is independently programmed with an external resistor. Synchronous rectifier timing is adjustable to optimize efficiency. A UVLO program input provides precise system turn-on and turn off voltages. The LTC3723-1 features peak current mode control with programmable slope compensation and leading edge blanking, while the LTC3723-2 employs voltage mode control with voltage feedforward capability.The LTC3723-1/LTC3723-2 feature extremely low operating and start-up currents. Both devices provide reliable short-circuit and over temperature protection. The LTC3723-1/LTC3723-2 are offered in a 16-pin SSOP package.ApplicationsTelecommunications, Infrastructure Power SystemsDistributed Power Architectures

The LTC3725 is a controller for a single-switch forward converter and includes an on-chip gate driver.For secondary-side control, combine the LTC3725 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 LTC3725 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