2.5A, 15V Synchronous Buck Boost DC/DC Converter Enables a Multitude of Input Sources
Linear Technology announces the LTC3112, a synchronous buck-boost converter that delivers up to 2.5A of output current from a wide range of power sources, including single or multiple cell batteries, super capacitor stacks and wall adapters. Its 2.7V to 15V input range and 2.5V to 14V output range provides a regulated output with inputs above, below or equal to the regulated output. The low noise buck-boost topology incorporated in the LTC3112 provides a continuous, jitter-free transition between buck and boost modes, making it ideal for RF and other noise-sensitive applications that must maintain a low-noise constant output voltage with a variable input power source. In many applications, battery run time is significantly extended over step-down only solutions. The LTC3112's default 750kHz switching frequency, that can be synchronized to an external 300KHz to 1.5MHz clock, and proprietary third generation buck-boost PWM circuitry ensure low noise and high efficiency while minimizing the size of external components. The combination of tiny externals and a 4mm x 5mm DFN or TSSOP-20E package provides a compact solution footprint. The LTC3112 includes four internal low RDS(ON) N-channel MOSFETs to deliver efficiencies of up to 95%. User-selectable Burst Mode® operation lowers quiescent current to only 50μA, improving light load efficiency and extending battery run time. For noise-sensitive applications, Burst Mode operation can be disabled. The LTC3112 also offers an integrated output current monitor that enables the load current to be monitored or controlled to a constant value. Other features include soft-start, overvoltage protection, short circuit protection, thermal shutdown and output disconnect. Summary of Features: LTC3112
Linear Technology Corporation announces the LT3694, a 2.6A, 36V step-down switching regulator with dual linear controllers, packaged in a 4mm x 5mm QFN or TSSOP-20E. The LT3694 operates from a VIN range of 4V to 36V with transient protection to 70V, making it ideal for load dump and cold-crank conditions found in automotive applications. Its internal 3.5A switch can deliver up to 2.6A of continuous output current at voltages as low as 0.75V. Its switching frequency is user-programmable from 250kHz to 2.5MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. Each integrated LDO controller has an accurate programmable current limit up to 1A to provide an additional level of reliability. Combined with NPN transistors, they can be used to offer dual low noise outputs in addition to the primary channel. Although the LDO controllers can be powered by independent inputs, powering them from the primary switching output ensures both high efficiency and low noise. The combination of its 4mm x 5mm QFN package (or thermally enhanced TSSOP-20E) and high switching frequency, which keeps external capacitors and inductors small, provides a compact, thermally efficient footprint. The LT3694's main switcher utilizes a high efficiency 3.5A switch, with the necessary oscillator, control, logic circuitry and LDO controllers integrated into a single die. Special design techniques enable high efficiency over a wide input voltage range and its current mode topology enables fast transient response and excellent loop stability. A diode current limit pin offers an additional level of overload protection. Other features include a power good flag, independent tracking/soft-start pins and programmable undervoltage lockout. Summary of Features: LT3694/-1
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