Linear Maximizes Energy Conversion and Launches Hot Swap Devices

Date
01/07/2011

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Synchronous Buck-Boost DC/DC Converter Offers Low Noise Operation & Extended Run Time from Batteries or Supercapacitors

2MHz, 3A (IOUT) Synchronous Buck-Boost Switching Regulator

Linear Technology announces the LTC3113, a synchronous buck-boost converter that delivers 3A of output current from a nominal 3.3V power source, Li-Ion/Polymer battery or up to 1A from dual cell alkaline/NiCad/NiMH batteries. The LTC3113's 1.8V to 5.5V input range and 1.8V to 5.5V output range provides a regulated output from an input voltage above, below or equal to the output. The LTC3113 is also an ideal regulator solution to maximize the energy available from a two supercapacitor stack. The proprietary buck-boost topology incorporated in the LTC3113 delivers a continuous transition through all operating modes, making it ideal for demanding applications that must maintain a constant, low noise output voltage even as the input voltage declines below the output. In many cases, this can add up to 25% more battery run time compared to a buck regulator. The LTC3113's constant switching frequency is user programmable from 300kHz up to 2MHz in order to optimize the balance between efficiency and external component size. The combination of tiny externals and a 4mm x 5mm DFN or TSSOP-20E package provides unprecedented power density, typically required in many high performance applications. The LTC3113 includes two N-channel MOSFETs and two P-channel MOSFETs (RDS(ON) of 29mOhm and 40mOhm, respectively) to deliver efficiencies of up to 96%. User-selectable Burst Mode® operation lowers quiescent current to only 40uA, improving light load efficiency and further extending battery run time. For noise sensitive applications, the Burst Mode operation can be disabled, offering the lowest noise operation. Other features include soft-start, current limiting, thermal shutdown and output disconnect. Summary of Features: LTC3113

  • 3A Synchronous Buck-Boost Regulator
  • Regulated Output with Input Voltage Above, Below or Equal to the Output Voltage
  • 1.8V to 5.5V Input & Output Voltage Range
  • Up to 3A Continuous Output Current
  • Single Inductor
  • Low Noise Buck-Boost Architecture
  • Up to 96% Efficiency
  • Programmable Frequency from 300kHz to 2MHz
  • Selectable Burst Mode® Operation
  • Output Disconnect in Shutdown
  • Shutdown Current: <1uA
  • Internal Soft-Start
Small, Thermally Enhanced 16-Lead (4mm × 5mm × 0.75mm) DFN Package or 20-Lead TSSOP Package LTC3113EDHD is available in a 16-lead 4mm x 5mm DFN package and the LTC3113EFE is in a thermally enhanced 20-lead TSSOP package. Industrial grade versions, the LTC3113IDHD and LTC3113IFE, are guaranteed to operate over the -40°C to 125°C operating junction temperature range. All versions are available from stock. For more information, visit www.linear.com/3113.

Linear Technology Corporation introduces the LTC4312 and LTC4314 2-wire bus multiplexers, which provide individual enable pins to connect an upstream I2C bus to any combination of downstream busses or cards. The LTC4312 and LTC4314 are pin-selectable multiplexers with bus buffers that reduce component count while promoting ideal I2C signal integrity. The LTC4312 multiplexes two channels, while the LTC4314 multiplexes four channels. These devices allow easy I2C address expansion, providing the ability to address one of multiple identical devices, thus resolving address conflict issues. Bidirectional capacitive buffering allows extension of the I2C bus size well beyond the 400pF I2C bus specification and prevents I2C signal corruption during live board insertion or removal.

The LTC4312 and LTC4314 are suitable for a wide range of applications, including radial architectures in telecommunications systems such as ATCA, address expansion and level translators. Many I2C and SMBus devices operate at different supply voltage levels, yet must communicate in the same application. The LTC4312 and LTC4314 support level-translation for bus voltages ranging from 1.5V to 5.5V providing the ability to power devices from different supply voltages while maintaining fully bidirectional communications between all devices in the system. Bidirectional buffering keeps backplane and card capacitances isolated, while maintaining low offsets and high noise margins up to 0.3VCC. In addition, built-in rise time accelerators provide strong pull-up currents on SCL and SDA rising edges to meet I2C rise time specifications for heavily loaded busses; the strength of these accelerators can be selected or disabled completely. Safety measures include a stuck bus disconnect and recovery feature to disengage the input from all enabled output channels and issue clocks to the stuck device, a fault output to signal when the host a bus is stuck low, and 4kV HBM ESD protection for increased ruggedness. Summary of Features: LTC4312-14

  • 1:4 Multiplexer/Switch for 2-Wire Bus (LTC4314)
  • 1:2 Multiplexer/Switch for 2-Wire Bus (LTC4312)
  • Bidirectional Buffer for SDA & SCL Lines
  • High Noise Margin with VIL = 0.3•VCC
  • ENABLE Pins Connect SDA & SCL Lines
  • Selectable Rise Time Accelerator Current & Activation Voltage
  • Level Shift 1.5V, 1.8V, 2.5V, 3.3V & 5V Busses
  • Prevents SDA and SCL Corruption During Live Board
  • Stuck Bus Disconnect & Recovery
  • Compatible with I2C, I2C Fast Mode & SMBus
  • 4kV Human Body Model ESD Ruggedness
  • 14-Lead DFN & 16-Lead MSOP Packages (LTC4312)
  • 20-Lead SSOP & 3mm x ?4mm QFN Packages (LTC4314) The LTC4312 is available in 14-lead 4mm x 3mm DFN and 16-lead SSOP packages, and the LTC4314 is available in 20-lead 3mm x 4mm QFN and 20-lead SSOP packages. For more information, visit: www.linear.com/4312 and www.linear.com/4314 www.linear.com

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