Analog Devices

The LTC3419 is a dual, 2.25MHz, constant-frequency, synchronous step-down DC/DC converter in a tiny 3mm × 3mm DFN package. 100% duty cycle provides low dropout operation, extending battery life in portable systems. Low output voltages are supported with the 0.6V feedback reference voltage. Each regulator can supply 600mA output current.The input voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications. Supply current during operation is only 35µA and drops to <1µA in shutdown. A user-selectable mode input allows the user to trade off between high efficiency Burst Mode operation and pulse-skipping mode.An internally set 2.25MHz switching frequency allows the use of tiny surface mount inductors and capacitors. Internal soft-start reduces inrush current during start-up. Both outputs are internally compensated to work with ceramic output capacitors. The LTC3419 is available in a low profile (0.75mm) 3mm × 3mm DFN package. The LTC3419 is also available in a fixed output voltage configuration selected via internal resistor dividers.ApplicationsCellular TelephonesDigital Still CamerasWireless and DSL ModemsPortable Media PlayersPDAs/Palmtop PCs

The LTC3421 is a high efficiency, current mode, fixed frequency, step-up DC/DC converter with true output disconnect and inrush current limiting. The device includes a 0.10Ω N-channel MOSFET switch and a 0.14Ω P-channel synchronous rectifier. This product has the ability to simply program the output voltage, switching frequency, current limit, soft-start, Burst Mode threshold and loop compensation with external passive components.Quiescent current is only 12µA during Burst Mode operation, maximizing battery life in portable applications. The oscillator frequency can be programmed up to 3MHz and can be synchronized to an external clock applied to the SYNC pin. An open-drain uncommitted low-battery comparator is included. The part maintains operation in applications with a secondary cell powering the output voltage during shutdown.Other features include: 1µA shutdown, anti-ringing control, thermal limit and reference output.The LTC3421 is available in a small 4mm × 4mm QFN package.ApplicationsHandheld ComputersCordless PhonesGPS ReceiversBattery Backup Supplies

The LTC3423 and LTC3424 are high efficiency, fixed frequency, step-up DC/DC converters that can regulate output voltages as low as 1.5V from a single cell. An applied voltage of at least 2.7V to the VDDpin is required to power the internal control circuitry.The devices include a 0.16Ω N-channel MOSFET switch and a 0.21Ω P-channel synchronous rectifier. The LTC3423 is intended for applications requiring less than 0.75W of output power and the LTC3424 for 1.5W or less. Switching frequencies up to 3MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock.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 the operation is at constant fixed frequency.Other features include a 1µA shutdown, thermal shutdown and current limit. The LTC3423 and LTC3424 are available in the 10-lead MSOP package. For applications requiring an output voltage greater than 2.6V, the LTC3401 and LTC3402 are recommended without the need of a separate voltage for the VDDpin.ApplicationsPagersHandheld InstrumentsCordless PhonesWireless HandsetsGPS ReceiversBattery Backup

The LTC3423 and LTC3424 are high efficiency, fixed frequency, step-up DC/DC converters that can regulate output voltages as low as 1.5V from a single cell. An applied voltage of at least 2.7V to the VDDpin is required to power the internal control circuitry.The devices include a 0.16Ω N-channel MOSFET switch and a 0.21Ω P-channel synchronous rectifier. The LTC3423 is intended for applications requiring less than 0.75W of output power and the LTC3424 for 1.5W or less. Switching frequencies up to 3MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock.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 the operation is at constant fixed frequency.Other features include a 1µA shutdown, thermal shutdown and current limit. The LTC3423 and LTC3424 are available in the 10-lead MSOP package. For applications requiring an output voltage greater than 2.6V, the LTC3401 and LTC3402 are recommended without the need of a separate voltage for the VDDpin.ApplicationsPagersHandheld InstrumentsCordless PhonesWireless HandsetsGPS ReceiversBattery Backup

The LTC3425 is a synchronous, 4-phase boost converter with output disconnect capable of operation below 1V input. It includes four N-channel MOSFET switches and four P-channel synchronous rectifiers for an effective RDS(ON)of 0.045Ω and 0.05Ω, respectively. 4-phase operation greatly reduces peak inductor currents, and capacitor ripple current, and increases effective switching frequency, minimizing inductor and capacitor sizes. True output disconnect eliminates inrush current and allows zero load current in shutdown. External Schottky diodes are not required in most applications (VOUT< 4.3V). Power saving Burst Mode operation can be user controlled or left in automatic mode.Other features include 1µA shutdown current, programmable frequency with sync in and out, programmable soft-start, antiringing control, thermal shutdown, adjustable current limit, reference output and power good comparator.The LTC3425 is available in a small, thermally enhanced 32-pin QFN package.ApplicationsHandheld ComputersPoint-of-Load Regulators3.3V to 5V Conversion

The LTC3426 step-up switching regulator generates an output voltage of up to 5.5V from an input voltage as low as 1.6V. Ideal for applications where space is limited, it switches at 1.2MHz, allowing the use of tiny, low cost and low profile external components. Its internal 2A, 100mΩ NMOS switch provides high efficiency even at heavy load, while the constant frequency, current mode architecture results in low, predictable output noise that is easy to filter.Anti-ringing circuitry reduces EMI concerns by damping the inductor while in discontinuous mode, and internal soft-start eases inrush current worries. Internal frequency compensation is designed to accommodate ceramic output capacitors, further reducing noise. The device features very low shutdown current of 0.5µA.The LTC3426 is available in the 6-lead SOT-23 package.Protected by U.S. Patents, including 6498466, 6611131ApplicationsWhite LED Driver SupplyLocal 3.3V or 5V SupplyBattery Back-Up

The LTC3428 is a 2-phase, current mode boost converter, capable of supplying 2A at 5V from a 3.3V input. Two 93mΩ, 2A N-channel MOSFET switches allow the LTC3428 to deliver high efficiency from input voltages as low as 1.6V.External parts count and size are minimized by a 1MHz switching frequency and a 2-phase design. Two phase operation significantly reduces peak inductor currents and capacitor ripple current, doubling the effective switching frequency and minimizing inductor and capacitor size. External compensation allows the feedback loop response to be optimized for a particular application.Other features include: an active low shutdown pin reduces supply current to below 1µA, internal soft-start, antiringing control and thermal shutdown. The LTC3428 is available in a low profile (0.75mm) 10-lead (3mm × 3mm) DFN package.ApplicationsNetworking EquipmentHandheld InstrumentsDigital CamerasDistributed PowerLocal 3.3V to 5V Conversion

The LTC3429/LTC3429B are high efficiency synchronous, fixed frequency, step-up DC/DC converters with true output load disconnect, inrush current limiting and softstart in a low profile 6-lead ThinSOTTMpackage. These devices are capable of supplying 100mA from a single AA cell input or 250mA from a 2-cell AA with a 3.3V output.A switching frequency of 500kHz minimizes overall solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. Current mode PWM control with internal compensation reduces external parts count thereby saving critical board real estate. The LTC3429 shifts automatically to power saving Burst Mode operation at light loads while the LTC3429B features continuous switching at light loads. Antiringing control circuitry reduces EMI concerns by damping the inductor in discontinuous mode.The devices also feature low shutdown current of under 1µA. The true output disconnect feature allows the output to be completely discharged in shutdown. It also limits the inrush of current during start-up, minimizing surge currents seen by the input supply.ApplicationsMP3 PlayersDigital CamerasLCD Bias SuppliesHandheld InstrumentsWireless HandsetsGPS Receivers

The LTC3440 is a high efficiency, fixed frequency, Buck-Boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single lithium-ion, multicell alkaline or NiMH applications where the output voltage is within the battery voltage range.The device includes two 0.19Ω N-channel MOSFET switches and two 0.22Ω P-channel switches. Switching frequencies up to 2MHz are programmed with an external resistor and the oscillator can be synchronized to an external clock. Quiescent current is only 25µA 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, soft-start control, thermal shutdown and current limit. The LTC3440 is available in the 10-pin thermally enhanced MSOP package.Protected by U.S. Patents including 6404251, 6166527.ApplicationsPalmtop ComputersHandheld InstrumentsMP3 PlayersDigital Cameras

The LTC3442 is a highly efficient, fixed frequency, Buck-Boost DC/DC converter, which operates from input voltages above, below, and equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for a single Lithium-Ion or multicell alkaline applications where the output voltage is within the battery voltage range.The device includes two 0.10Ω N-channel MOSFET switches and two 0.10 Ohm P-channel switches. Operating frequency and average input current limit can each be programmed with an external resistor. Quiescent current is only 35µA in Burst Mode operation, maximizing battery life in portable applications. Automatic Burst Mode operation allows the user to program the load current for Burst Mode operation, or to control it manually.Other features include 1µA shutdown current, programmable soft-start, peak current limit and thermal shutdown. The LTC3442 is available in a low profile, thermally enhanced 12-lead (4mm × 3mm × 0.75mm) DFN package.ApplicationsPDA/'SMART' PhonesHandheld ComputersMP3 PlayersHandheld InstrumentsDigital CamerasWireless HandsetsUSB Peripherals