Analog Devices Inc./Maxim Integrated

The LT3844 is a DC/DC controller used for medium power, low part count, high efficiency supplies. It offers a wide 4V to 60V input range (7.5V minimum startup voltage) and can implement step-down, step-up, inverting and SEPIC topologies.The LT3844 includes Burst Mode operation, which reduces quiescent current below 120µA and maintains high efficiency at light loads. An internal high voltage bias regulator allows for simple biasing.Additional features include current mode control for fast line and load transient response; programmable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications; a gate driver capable of driving large N-channel MOSFETs; a precision undervoltage lockout function; 10µA shutdown current; short-circuit protection and a programmable soft-start function.The LT3844 is available in a 16-lead thermally enhanced TSSOP package.ApplicationsIndustrial Power Distribution12V and 42V Automotive and Heavy EquipmentHigh Voltage Single Board SystemsDistributed Power SystemsAvionicsTelecom Power

The LT3845A is a high voltage, synchronous, current mode controller used for medium to high power, high efficiency supplies. It offers a wide 4V to 60V input range (7.5V minimum start-up voltage). An onboard regulator simplifies the biasing requirements by providing IC power directly from VIN.Burst Mode®operation maintains high efficiency at light loads by reducing IC quiescent current to 120μA. Light load efficiency is also improved with the reverse inductor current inhibit function which supports discontinuous operation.Additional features include adjustable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications, gate drivers capable of driving large N-channel MOSFETs, a precision undervoltage lockout, 10μA shutdown current, short-circuit protection and a programmable soft-start.The LT3845A is available in a 16-lead thermally enhanced TSSOP package.FeaturesLT3845-LT3845AImproved Performance In Over Current ConditionsApplications12V and 42V Automotive and Heavy Equipment48V Telecom Power SuppliesAvionics and Industrial Control SystemsDistributed Power Converters

The LT3905 is a fixed frequency current-mode step-up converter designed to bias avalanche photodiodes (APD) in optical receivers. The LT3905 features high side APD current monitoring over four decades of dynamic range with better than 2% relative accuracy over the 3μA to 3mA range.The maximum APD current is programmed with a single resistor, and a fast current limiter with indicator protects the APD during overload conditions. Adjustable output voltage provides dynamic bias control, and an adjustable loss-of-signal indicator flags low APD current.Coupled with the integrated DMOS power switch and Schottky rectifier, the LT3905 provides a compact total solution with few external components and low solution cost. Constant switching frequency results in predictable output noise that is easy to filter.The LT3905 is available in the tiny footprint (3mm × 3mm) 16-Lead QFN Package.ApplicationsAPD BiasPIN Diode BiasOptical Receivers and ModulesFiber Optic Network Equipment

The LT3922 is a monolithic, synchronous, step-up DC/DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. The LT3922 will maintain ±2.5% current regulation through an external sense resistor over a wide range of output voltages.The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3922 also includes a driver for an external high side PMOS for PWM dimming and an internal PWM signal generator for analog control of PWM dimming when an external signal is not available.Additional features include an accurate external reference voltage for use with the CTRL and PWM pins, an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions, and thermal shutdown.APPLICATIONSAutomotive and Industrial LightingMachine Vision

The LT3922-1 is a monolithic, synchronous, step-up DC/ DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. The LT3922-1 will maintain ±2.5% current regulation through an external sense resistor over a wide range of output voltages.The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3922-1 also includes a driver for an external high side PMOS for PWM dimming and an internal PWM signal generator for analog control of PWM dimming. When an external signal is available, the LT3922-1 can perform 25,000:1 PWM dimming with 100Hz PWM pulses.Additional features include an accurate external reference voltage for use with the CTRL and PWM pins, an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions, and thermal shutdown.APPLICATIONSAutomotive and Industrial LightingMachine Vision

The LT3935 is a monolithic, synchronous, step-down DC/DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. An output voltage limit can be set with a resistor divider to the FB pin.The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI.Additional features include an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions, and thermal shutdown. The LT3935 utilizes proprietary Silent Switcher technology for very low EMI.APPLICATIONSAutomotive LightingIndustrial and General Purpose Lighting