Analog Devices Inc./Maxim Integrated

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

The LTC3443 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 part is pin for pin compatible with its predecessor, the LTC3441, with a lower operating frequency (600kHz), and a VCpin clamp circuit during Burst Mode operation. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single Lithium Ion or multi-cell applications where the output voltage is within the battery voltage range.The device includes two 0.10Ω N-channel MOSFET switches and two 0.11Ω P-channel switches. External Schottky diodes are optional, and can be used for a moderate efficiency improvement. The operating frequency is internally set to 600kHz and can be synchronized up to 1.2MHz. Quiescent current is only 28µA 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 is driven low or with a clock, then fixed frequency switching is enabled.Other features include a 1µA shutdown, soft-start control, thermal shutdown and current limit. The LTC3443 is available in a thermally enhanced 12-lead (4mm × 3mm) DFN Package.ApplicationsHandheld ComputersHandheld InstrumentsMP3 PlayersDigital Cameras

The LTC3445 contains a high efficiency monolithic synchronous current mode buck regulator, two LDO regulators, a PowerPath™controller and an I2C™interface.The buck regulator has a 6-bit programmable output range of 0.85V to 1.55V. Also, the buck regulator uses either a constant (1.5MHz) or a spread spectrum switching frequency. Using the spread spectrum option allows for a lower noise regulated output as well as low noise at the input. In addition, the regulated output voltage slew rate is programmable via the I2C interface.The LTC3445 contains two LDO voltage regulators. The regulator output voltages are externally resistor programmable. Each LDO is capable of delivering up to 50mA.The LTC3445 contains control circuitry (PowerPath) for automatic back-up battery selection. VBACKUPis typically a coin cell.Typical supply current during operation is only 360µA and drops to 27µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3445 ideal for single Li-Ion battery-powered applications. Automatic Burst Mode®operation increases efficiency at light loads, further extending battery life.Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, Spread Spectrum patent pending.ApplicationsIntel’s Microprocessor Supply (PXA27X)Portable Instruments

The LTC3446 combines a synchronous buck DC/DC converter with two very low dropout (VLDO) linear regulators to provide up to three stepped-down output voltages from a single input voltage. The input voltage range is ideally suited for Li-Ion battery-powered applications, as well as powering low voltage logic from 5V or 3.3V rails. The output voltage range extends down to 0.4V for the VLDO regulators and 0.8V for the buck.The 1A synchronous buck converter provides the main output with high efficiency, typically 85%. The two 300mA VLDO regulators can run off the main output to provide two additional lower voltage outputs. A built-in supply monitor provides a power good indication.The buck converter switches at 2.25MHz, allowing the use of small surface mount inductors and capacitors. Constant frequency current mode operation produces controlled output spectrum and fast transient response. A mode-select pin allows automatic Burst Mode operation to be enabled for higher efficiency at light load, or disabled for lower noise operation down to very light loads. The two VLDO regulators are stable with ceramic output capacitors as small as 1µF.ApplicationsLow Power Handheld DevicesLow Voltage and Multivoltage Power for Digital Logic, I/O, FPGAs, CPLDs, ASICs and CPUs

The LTC3448 is a high efficiency, monolithic, synchronous buck regulator using a constant frequency, current mode architecture. Supply current during operation is only 32µA (linear regulator mode) and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3448 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. At moderate output load levels, PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications.The LTC3448 automatically switches into linear regulator operation at very low load currents to maintain <5mVP-Poutput voltage ripple. Supply current in this mode is typically 32µA. The switch to linear regulator mode occurs at a threshold of 3mA. Linear regulator operation can be set to on, off or automatic turn on/off.Switching frequency is selectable at either 1.5MHz or 2.25MHz, allowing the use of small surface mount inductors and capacitors.The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. The LTC3448 is available in a low profile 3mm × 3mm DFN package or thermally enhanced 8-lead MSOP.Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. Others pending.ApplicationsCellular TelephonesPersonal Information AppliancesWireless and DSL ModemsDigital Still CamerasMP3 PlayersPortable Instruments

The LTC3450 is a complete power converter solution for small thin film transistor (TFT) liquid crystal display (LCD) panels. The device operates from a single Lithium-Ion cell, 2- to 3-cell alkaline input or any voltage source between 1.5V and 4.6V.The synchronous boost converter generates a low noise, high efficiency 5.1V, 10mA supply. Internal charge pumps are used to generate 10V, 15V, and -5V, -10V or -15V. Output sequencing is controlled internally to insure proper initialization of the LCD panel.A master shutdown input reduces quiescent current to <2µA and quickly discharges each output for rapid turn off of the LCD panel. The LTC3450 is offered in a low profile (0.75mm), 3mm × 3mm 16-pin QFN package, minimizing the solution profile and footprint.ApplicationsCellular Handsets with Color DisplayHandheld InstrumentsPDA

The LTC3452 is a synchronous buck-boost DC/DC converter optimized for driving two banks of white LEDs from a single Li-Ion battery input. Five parallel LEDs can be driven at up to 25mA each in the low power LED bank, while two LEDs can be driven at up to 150mA each (or a single LED at 300mA) in the high power LED bank. The regulator operates in either synchronous buck, synchronous boost or buck-boost mode, depending on input voltage and LED maximum forward voltage. Optimum efficiency is achieved by sensing which LED requires the largest forward voltage drop at its programmed current, and regulating the common output rail for lowest dropout. Efficiency of 85% can be achieved over the entire usable range of a Li-Ion battery (2.7V to 4.2V).Maximum LED current for each LED display is programmable with a single external resistor. Dual enable pins allow for PWM brightness control in the low power bank and independent on/off control for the high current bank (optimal for LED camera flash). In shutdown, the supply current is only 6.5µA.A high constant operating frequency of 1MHz allows the use of a small external inductor. The LTC3452 is offered in a low profile (0.75mm) thermally enhanced 20-lead (4mm × 4mm) QFN package.ApplicationsCell PhonesDigital CamerasPDAsPortable Devices