Analog Devices Inc./Maxim Integrated

The LTC3374A is a multioutput power supply IC consisting of eight synchronous 1A buck converters, all powered from independent 2.25V to 5.5V input supplies. An upgraded pin-compatible version of the LTC3374, the LTC3374A, has higher efficiency, improved output voltage accuracy and an added overvoltage (OV) indicator.The DC/DCs may be used independently or in parallel to achieve higher output currents of up to 4A with a shared inductor. The common buck switching frequency may be programmed with an external resistor, synchronized to an external oscillator, or set to a default internal 2MHz clock. The operating mode for all DC/DCs may be programmed via the MODE pin.To reduce input noise the buck converters are phased in 90° steps. Precision enable pin thresholds simplify powerup sequencing. The LTC3374A is available in a 38-lead 5mm × 7mm QFN package as well as a 38-lead exposed pad TSSOP package.NOTESLTC3374LTC3374AHigher efficiency, improved output voltage accuracy and an added overvoltage (OV) indicatorAPPLICATIONSGeneral Purpose Multichannel Power SuppliesIndustrial/Automotive/Communications

The LTC3376 is a highly flexible multioutput power supply IC. The device includes four synchronous buck converters, configured to share eight 1.5A power stages, powered from independent 3V to 20V inputs. The DC/DCs are assigned to one of fifteen power configurations via pin strappable CFG0 to CFG3 pins. The LTC3376 includes the integration of ceramic capacitors into the package for the BST pins thereby saving PCB space. The common buck switching frequency may be programmed with an external resistor, synchronized to an external oscillator, or set to a default internal 2MHz clock.The operating mode for all DC/DCs may be programmed via the SYNC/MODE pin for Burst Mode or forced continuous mode operation. The PGOOD1 to PGOOD4 outputs indicate when each enabled DC/DC is within a specified percentage of its final output.Current monitors allow for external monitoring of each buck’s load. The EXTVCCpin allows for the internal circuitry to run from a 3V to 5.5V rail for improved efficiency.Precision RUN pin thresholds facilitate power-up sequencing. The LTC3376 is available in a 64 lead 7mm × 7mm BGA (0.8mm ball pitch).ApplicationsTelecom/Industrial12V Distributed Power Systems

The LTC3400/LTC3400B are synchronous, fixed frequency, step-up DC/DC converters delivering high efficiency in a 6-lead ThinSOT™package. Capable of supplying 3.3V at 100mA from a single AA cell input, the devices contain an internal NMOS switch and PMOS synchronous rectifier.A switching frequency of 1.2MHz minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. The current mode PWM design is internally compensated, reducing external parts count.The LTC3400 features automatic shifting to power saving Burst Mode operation at light loads, while the LTC3400B features continuous switching at light loads. Antiringing control circuitry reduces EMI concerns by damping the inductor in discontinuous mode, and the devices feature low shutdown current of under 1µA.Both devices are available in the low profile (1mm) SOT-23 package.FeaturesLTC3400Burst ModeLTC3400BBurst Mode DisabledLTC3400-1Connects Vin To Vout In ShutdownApplicationsPagersMP3 PlayersDigital CamerasLCD Bias SuppliesHandheld InstrumentsWireless HandsetsGPS Receivers

The LTC3400-1 is a synchronous, fixed frequency, stepup DC/DC converter delivering high efficiency in a 6-lead ThinSOT™package. Capable of supplying 3.3V at 100mA from a single AA cell input, the device contains an internal NMOS switch and PMOS synchronous rectifier.A switching frequency of 1.2MHz minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. The current mode PWM design is internally compensated, reducing external parts count. The LTC3400-1 features automatic shifting to power saving Burst Mode operation at light loads. In shutdown, VOUTand VINare connected, which allows the input battery to be used for backup power. The LTC3400-1 features low shutdown current of under 1µA.The LTC3400-1 is offered in the low profile (1mm)SOT-23 package.US Patent Numbers 5,481,178; 6,580,258; 6,304,066; 6,127,815; 6,498,466; 6,611,131.FeaturesLTC3400Burst ModeLTC3400BBurst Mode DisabledLTC3400-1Connects Vin to Vout In ShutdownApplicationsPagersMP3 PlayersDigital CamerasLCD Bias SuppliesHandheld InstrumentsWireless HandsetsGPS Receivers

The LTC3402 is a high efficiency, fixed frequency, step-up DC/DC converter that operates from an input voltage below 1V. The device includes a 0.16Ω N-channel MOSFET switch and a 0.18Ω P-channel synchronous rectifier. Switching frequencies up to 3MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock. An external Schottky diode is optional but will slightly improve efficiency.Quiescent current is only 38µA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin has either a clock or is driven low, then fixed frequency switching is enabled.Other features include a 1µA shutdown, antiringing control, open-drain power good output, thermal shutdown and current limit. The LTC3402 is available in the 10-lead thermally enhanced MSOP package. Lower current applications should use the 1A rated LTC3401 synchronous boost converter. Applications that require VOUT< 2.6V should use the LTC3424.ApplicationsCellular TelephonesHandheld ComputersMP3 Players2-Way PagersGPS ReceiversBattery Backup SuppliesCCFL Backlights