Analog Devices Inc./Maxim Integrated

The LTC3454 is a synchronous buck-boost DC/DC converter optimized for driving a single high power LED at currents up to 1A from a single cell Li-Ion battery input. The regulator operates in either synchronous buck, synchronous boost, or buck-boost mode depending on input voltage and LED forward voltage. PLED/PINefficiency greater than 90% can be achieved over the entire usable range of a Li-Ion battery (2.7V to 4.2V).LED current is programmable to one of four levels, including shutdown, with dual external resistors and dual enable inputs. In shutdown no supply current is drawn.A high constant operating frequency of 1MHz allows the use of small external components.The LTC3454 is offered in a low profile (0.75mm) thermally enhanced 10-lead (3mm × 3mm) DFN package.ApplicationsCell Phone Camera FlashCell Phone Torch LightingDigital CamerasPDAsMisc Li-Ion LED Drivers

The LTC3455/LTC3455-1 are complete power management solutions for a variety of portable applications. These devices contain two synchronous step-down DC/DC converters, a USB power controller, a full-featured Li-Ion battery charger, a Hot Swap output, a low-battery indicator, and numerous internal protection features. The LTC3455/LTC3455-1 provide a small, simple solution for obtaining power from three different power sources: a single-cell Li-Ion battery, a USB port, and a wall adapter. Current drawn from the USB bus is accurately limited under all conditions. Whenever a USB or a wall adapter is present, the battery charger is enabled and all internal power for the device is drawn from the appropriate external power source. All outputs are discharged to ground during shutdown to provide complete output disconnect. These devices are available in a 4mm × 4mm 24-pin exposed-pad QFN package.ApplicationsHandheld ComputersDigital CamerasMP3 Players

The LTC3456 is a complete power management system IC optimized for a variety of portable applications. The device generates two separate power rails: a 3.3V (fixed) Main supply and a 1.8V (adjustable) Core supply. In addition, the LTC3456 contains a USB power manager, a Hot Swap output, a low-battery indicator and an alwaysalive VMAXoutput. The LTC3456 takes power from one of three sources: a Wall adapter, a USB port or a 2-cell Alkaline/NiCd/NiMH battery, in that order of priority. Current drawn from the USB port is accurately limited to 100mA or 500mA based on the state of the USBHP pin.The Main and Core switchers are all high efficiency, 1MHz fixed frequency PWM converters. Availability in a small (4mm × 4mm × 0.75mm) 24-pin QFN package makes the LTC3456 ideal for space-sensitive portable devices.ApplicationsGPS Portable NavigatorsMP3 PlayersDigital CamerasHandheld Computers

The LTC3458L is a high efficiency, current mode, fixed frequency, step up DC/DC converter with true output disconnect and inrush current limiting. The LTC3458L is rated for up to 6V output and includes a 0.2Ω N-channel MOSFET switch and a 0.3Ω P-channel MOSFET synchronous rectifier. The LTC3458L is well suited for battery powered applications and includes programmable output voltage, switching frequency and loop compensation. The oscillator frequency can be set up to 1.5MHz or synchronized to an external clock.Quiescent current is only 12µA during Burst Mode operation maximizing battery life in portable applications. The Burst Mode current threshold, peak current limit, and softstart are externally programmable. Other features include <1µA shutdown current, antiringing control, and thermal limit. The LTC3458L is available in a low profile (0.75mm), 4mm × 3mm 12-pin DFN package.Protected by U.S. Patents including 5481178, 6304066, 6580258, 5511131, 6498466Vout RangeSwitch CurrentLTC34582.0V to 7.5V1.4ALTC3458L2.0V to 6.0V1.7AApplicationsPoint-of-Load RegulatorsUSB VBUSPowerPortable GPSMP3 Players

The LTC3459 is a low current, high efficiency synchronous boost converter intended for low power, size constrained portable applications. The LTC3459 can be powered from a single lithium ion battery, a 2- to 3-cell stack of Alkaline or Nickel batteries, or any low impedance voltage source between 1.5V and 5.5V. The output is programmable via an external divider between 2.5V and 10V. Although the part is primarily intended for boost applications, VOUTwill maintain regulation below VIN(at reduced efficiency).The LTC3459 offers Burst Mode operation with a fixed peak current, providing high conversion efficiency over a wide range of load currents. During start-up, inductor current is controlled preventing the inrush surge current found in many boost converters. In shutdown the output is disconnected from the input and quiescent current is reduced to <1µA.The LTC3459 is offered in low profile 6-pin 2mm × 2mm DFN, 2mm × 3mm DFN or SOT-23 (ThinSOT) packages, allowing a tiny footprint for the total solution.ApplicationsGeneral Purpose Micropower BoostDigital CamerasPDAsLCD BiasSmall OLED DisplaysSupercap Charging