Analog Devices

The LT3519/LT3519-1/LT3519-2 are fixed frequency step-up DC/DC converters designed to drive LEDs. They feature an internal 45V, 750mA low side switch and Schottky diode. Combining a traditional voltage feedback and a unique rail-to-rail current sense feedback allows these converters to operate as a constant-voltage source or constant-current source. Internal compensation simplifies applications. These devices feature rail-to-rail LED current sense pins that provide the most flexibility in choosing a converter configuration to drive the LEDs. The LED current is externally programmable with a sense resistor. The external PWM provides up to 3000:1 PWM dimming and the CTRL input provides analog dimming.ApplicationsAutomotiveIndustrialConstant Current SourceCurrent Limited Constant Voltage Source

The LT3570 is a buck and boost converter with internal power switches and LDO controller. Each converter is designed with a 1.5A current limit and an input range from 2.5V to 36V, making the LT3570 ideal for a wide variety of applications. Switching frequencies up to 2.1MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock up to 2.75MHz.The LT3570 features a programmable soft-start function that limits the feedback voltage during start-up helping prevent overshoot and limiting inrush current. The LDO controller is capable of delivering up to 10mA of base current to an external NPN transistor.ApplicationsCable and Satellite Set-Top BoxesAutomotive SystemsTelecom Systems"Dying Gasp" SystemsTFT LCD Displays

The LT3571 is a current mode step-up DC/DC converter designed to bias avalanche photodiodes (APDs) in optical receivers with an output voltage up to 75V. The LT3571 features a high side fixed voltage drop APD current monitor with better than 10% relative accuracy over the entire temperature range. The integrated power switch, Schottky diode and APD current monitor allow a small solution footprint and low solution cost. It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source. The inductor-based topology ensures an input free from switching noise. The integrated high side current monitor produces a current proportional to the APD current with better than 10% relative accuracy over four decades of dynamic range in the input range of 250nA to 2.5mA. This current can be used as a reference to provide a digitally programmed output voltage via the CTRL pin. The LT3571 is available in the tiny footprint (3mm × 3mm) 16-lead QFN package.ApplicationsAPD BiasPIN Diode BiasOptical Receivers and ModulesFiber Optic Network Equipment

The LT3573 is a monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or opto-isolator is required for regulation. The part senses the isolated output voltage directly from the primary-side flyback waveform. A 1.25A, 60V NPN power switch is integrated along with all control logic into a 16-lead MSOP package.The LT3573 operates with input supply voltages from 3V to 40V, and can deliver output power up to 7W with no external power devices.The LT3573 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.ApplicationsIndustrial, Automotive and Medical Isolated Power Supplies

The LT3575 is a monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or optoisolator is required for regulation. The part senses the isolated output voltage directly from the primary side flyback waveform. A 2.5A, 60V NPN power switch is integrated along with all control logic into a 16-lead TSSOP package.The LT3575 operates with input supply voltages from 3V to 40V, and can deliver output power up to 14W with no external power switch.The LT3575 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.The output voltage is easily set with two external resistors and the transformer turns ratio. Off the shelf transformers are available for many applications.ApplicationsIndustrial, Automotive and Medical Isolated Power Supplies

The LT3580 is a PWM DC/DC converter containing an internal 2A, 42V switch. The LT3580 can be configured as either a boost, SEPIC or inverting converter. Capable of generating 12V at 550mA or –12V at 350mA from a 5V input, the LT3580 is ideal for many local power supply designs.The LT3580 has an adjustable oscillator, set by a resistor from the RT pin to ground. Additionally, the LT3580 can be synchronized to an external clock. The free running or synchronized switching frequency range of the part can be set between 200kHz and 2.5MHz.The LT3580 also features innovativeSHDNpin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function.Additional features such as frequency foldback and soft-start are integrated. The LT3580 is available in tiny 3mm × 3mm 8-lead DFN and 8-lead MSOP packages.ApplicationsVFD Bias SuppliesTFT-LCD Bias SuppliesGPS ReceiversDSL ModemsLocal Power Supply

The LT3581 is a PWM DC/DC converter with built-in fault protection features to aid in protecting against output shorts, input/output overvoltages, and overtemperature conditions. The part consists of a 42V master switch, and a 42V slave switch that can be tied together for a total current limit of 3.3A.The LT3581 is ideal for many local power supply designs. It can be easily configured in Boost, SEPIC, Inverting or Flyback configurations, and is capable of generating 12V at 830mA, or –12V at 625mA from a 5V input. In addition, the LT3581’s slave switch allows the part to be configured in high voltage, high power charge pump topologies that are very efficient and require fewer components than traditional circuits.The LT3581’s switching frequency range can be set between 200kHz and 2.5MHz. The part may be clocked internally at a frequency set by the resistor from the RT pin to ground, or it may be synchronized to an external clock. A buffered version of the clock signal is driven out of the CLKOUT pin, and may be used to synchronize other compatible switching regulator ICs to the LT3581.The LT3581 also features innovativeSHDNpin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function. Additional features such as frequency foldback and soft-start are integrated. The LT3581 is available in 14-Pin 4mm × 3mm DFN and 16-Lead MSE packages.ApplicationsLocal Power SupplyVacuum Fluorescent Display (VFD) Bias SuppliesTFT-LCD Bias SuppliesAutomotive Engine Control Unit (ECU) Power

The LT3585 series are highly integrated ICs designed to charge photoflash capacitors in digital and film cameras. A new control technique allows for the use of extremely small transformers. Each part contains an on-chip high voltage NPN power switch. Output voltage detection is completely contained within the part, eliminating the need for any discrete zener diodes or resistors. The output voltage can be adjusted by simply changing the turns ratio of the transformer.The CHRG/IADJ pin gives full control of the part to the user. Driving CHRG/IADJ low puts the part in low power shutdown. The CHRG/IADJ pin can also be used to reduce the input current of the charger, useful in extending battery life. TheDONEpin indicates when the part has completed charging.The LT3585 series of parts are housed in tiny 3mm × 2mm DFN packages.ApplicationsDigital/Film Camera FlashPDA/Cell Phone FlashEmergency Strobe

The LT3587 provides a one-chip solution for applications requiring two positive and one negative high voltage supplies.The LT3587 input voltage range of 2.5V to 6V makes it ideal for various battery-powered systems.A single resistor programs each of the three output voltage levels and the output current of Boost3. The intelligent soft-start allows for sequential soft-start of the Boost1 output followed by the negative output with a single capacitor. Internal sequencing circuitry also disables the inverter until the Boost1 output has reached 87% of its final value.The LT3587 integrates all the power switches, soft-start, and output-disconnect circuits into a small 3mm × 3mm QFN package. This high level of integration combined with small external components makes the LT3587 ideal for space constrained applications.ApplicationsDigital Still and Video CamerasScanner and Display SystemsPDA, Cellular Phones and Handheld ComputersLED Backlight and OLED Display DriversCCD Imager BiasGeneral High Voltage Supply Bias