The LTC3251/LTC3251-1.2/LTC3251-1.5 are 2-phase charge pump step-down DC/DC converters that produce a regulated output from a 2.7V to 5.5V input. The parts use switched capacitor fractional conversion to achieve twice the typical efficiency of a linear regulator. No inductors are required. VOUT is resistor programmable from 0.9V to 1.6V or fixed at 1.2V or 1.5V, with up to 500mA of load current available.A unique 2-phase spread spectrum architecture provides a very low noise regulated output as well as low noise at the input. The parts have four operating modes: Continuous Spread Spectrum, Spread Spectrum with Burst Mode operation, Super Burst? mode operation and shutdown.Low operating current (35?A in Burst Mode operation, 10?A in Super Burst mode operation) and low external parts count make the LTC3251/LTC3251-1.2/LTC3251-1.5 ideally suited for space-constrained battery-powered applications. The parts are short-circuit and over-temperature protected, and are available in a thermally enhanced 10-pin MSOP package.Applications Handheld Devices Cellular Phones Portable Electronic Equipment DSP Power Supplies

The LTC3729 is a multiple phase, synchronous step-down current mode switching regulator controller that drives N-channel external power MOSFET stages in a phase-lockable fixed frequency architecture. The PolyPhase controller drives its two output stages out of phase at frequencies up to 550kHz to minimize the RMS ripple currents in both input and output capacitors. The output clock signal allows expansion for up to 12 evenly phased controllers for systems requiring 15A to 200A of output current. The multiple phase technique effectively multiplies the fundamental frequency by the number of channels used, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.An internal differential amplifier provides true remote sensing of the regulated supply?s positive and negative output terminals as required for high current applications.A RUN/SS pin provides both 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 over a wide range of output capacitance and ESR values. The LTC3729 includes a power good output pin that indicates when the output is within ?7.5% of the designed set point. Vin Max Vref LTC3729 36V 0.8 LTC3729L-6 30V 0.6 Applications Desktop Computers Large Memory Arrays DC Power Distribution Systems

Demonstration circuit 541A is an isolated synchronous push-pull converter featuring the LTC3723-1, LTC3901, LT1431 and LT3710. The design provides an isolated 3.3V at 40A and 2.5V at 10A from a 48V telecom (36V to 72V) input voltage. Isolation voltage is 1500VDC. The demo board also can provide 3.3V @ 50A with the 2.5V output disabled.

The LT1934 is a micropower step-down DC/DC converter with internal 400mA power switch, packaged in a low profile (1mm) ThinSOT. With its wide input range of 3.2V to 34V, the LT1934 can regulate a wide variety of power sources, from 4-cell alkaline batteries and 5V logic rails to unregulated wall transformers and lead-acid batteries. Quiescent current is just 12?A and a zero current shutdown mode disconnects the load from the input source, simplifying power management in battery-powered systems. Burst Mode? operation and the low drop internal power switch result in high efficiency over a broad range of load current.The LT1934 provides up to 300mA of output current. The LT1934-1 has a lower current limit, allowing optimum choice of external components when the required output current is less than 60mA. Fast current limiting protects the LT1934 and external components against shorted outputs, even at 34V input.Applications Wall Transformer Regulation Automotive Battery Regulation Standby Power for Portable Products Distributed Supply Regulation Industrial Control Supplies

DC563A: Demo Board for the LTC2920 Single (-1) & Dual (-2) Margining Controller.

Demonstration Circuit 565 is a constant-frequency synchronous boost converter using the LTC3421. Guaranteed to start-up at 1V input voltage, this converter provides up to 95% efficiency. For 1.8V minimum input voltage, this converter can provide up to 1A load current. This converter has true output disconnect by eliminating body diode conduction of the internal PMOS rectifier. The output voltage is set at 3.3V. A different output voltage in the range of 2.4V to 5.25V can be obtained by changing one of the feedback resistors.

The LTC4053 is a standalone linear charger for lithium-ion batteries that can be powered directly from a USB port. The IC contains an on-chip power MOSFET and eliminates the need for an external sense resistor and blocking diode. Thermal regulation automatically adjusts charge current to limit die temperature during high power or high ambient temperature conditions. This feature protects the end product and the LTC4053 from thermal stress while the IC charges the battery at maximum rate without interruption.The charge current and charge time can be set externally with a single resistor and capacitor, respectively. When the input supply (wall adapter or USB supply) is removed, the LTC4053 automatically enters a low current sleep mode, dropping the battery drain current to less than 5?A.The LTC4053 also includes NTC temperature sensing, C/10 detection circuitry, AC present logic, low battery charge conditioning (trickle charging) and shutdown (25?A supply current).The LTC4053 is available in a 10-pin thermally enhanced MSOP package.Applications Cellular Telephones Handheld Computers Charging Docks and Cradles MP3 Players Digital Cameras

The LT3461/LT3461A are general purpose fixed frequency current mode step-up DC/DC converters. Both devices feature an integrated Schottky and a low VCESAT switch allowing a small converter footprint and lower parts cost. The LT3461 switches at 1.3MHz while the LT3461A switches at 3MHz. These high switching frequencies enable the use of tiny, low cost and low height capacitors and inductors. The constant switching frequency results in predictable output noise that is easy to filter, and the inductor based topology ensures an input free from switching noise typically present with charge pump solutions. The high voltage switch in the LT3461/LT3461A is rated at 40V making the device ideal for boost converters up to 38V.The LT3461/LT3461A are available in a low profile (1mm) SOT-23 package. Switching Frequency LT3461 1.3MHz LT3461A 3MHz Applications Digital Cameras CCD Bias Supply XDSL Power Supply TFT-LCD Bias Supply Local 5V or 12V Supply Medical Diagnostic Equipment Battery Backup

The LT3461/LT3461A are general purpose fixed frequency current mode step-up DC/DC converters. Both devices feature an integrated Schottky and a low VCESAT switch allowing a small converter footprint and lower parts cost. The LT3461 switches at 1.3MHz while the LT3461A switches at 3MHz. These high switching frequencies enable the use of tiny, low cost and low height capacitors and inductors. The constant switching frequency results in predictable output noise that is easy to filter, and the inductor based topology ensures an input free from switching noise typically present with charge pump solutions. The high voltage switch in the LT3461/LT3461A is rated at 40V making the device ideal for boost converters up to 38V.The LT3461/LT3461A are available in a low profile (1mm) SOT-23 package. Switching Frequency LT3461 1.3MHz LT3461A 3MHz Applications Digital Cameras CCD Bias Supply XDSL Power Supply TFT-LCD Bias Supply Local 5V or 12V Supply Medical Diagnostic Equipment Battery Backup

Demonstration circuit 653A is a dual 15A step-down DC/DC converter featuring the LTC3802EGN. The LTC3802EGN itself is a synchronous voltage mode controller. Output #1 of demonstration circuit 653A is a 3.3V / 15A rail and output #2 is a 2.5V / 15A rail. The input voltage range is 7V to 24V.The nominal switching frequency of the LTC3802 is 550kHz and its phase lockable synchronization range is 330kHz to 750kHz.