Datasheet Linear Technology LTC3440

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Design Notes

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  Single Inductor, Tiny Buck-Boost Converter Provides 95% Efficiency in Lithium-Ion to 3.3V Applications &mdash DN275
  PDF, 77 Kb, File published: Jan 1, 2002
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  Single Inductor, Tiny Buck-Boost Converter Provides 95%
  Efficiency in Lithium-Ion to 3.3V Applications – Design Note 275
  Mark Jordan
  Introduction
  In portable applications powered by a single lithium-ion
  cell, the input voltage can typically change from 4.2V
  initially, down to 2.5V at end of life. It is a challenging
  task to provide a regulated voltage within the range of
  the battery. Until now, the most popular solution has
  been the SEPIC converter, but its mediocre efficiency
  and requirement of both a coupled inductor and a high
  current flyback capacitor make it a less than optimal
  solution. Another option is to cascade a Boost converter with either an LDO or a Buck converter, but the
  additional area and cost of the extra components, as
  well as low efficiency, are major drawbacks. Linear
  Technology’s new LTC ®3440 Buck-Boost converter
  provides the most compact solution with the highest
  efficiency, thereby reducing cost, increasing battery
  life and saving precious real estate. light loads, the part offers user controlled Burst Mode В®
  operation to maximize battery life, drawing only 25ОјA
  of quiescent current. The operating frequency can be
  programmed from 300KHz to 2MHz by changing the
  value of the timing resistor on the RT pin. Users can …

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  Supply 2A Pulses for GSM Transmission from 500mA USB or PCMCIA Ports &mdash DN307
  PDF, 91 Kb, File published: Apr 1, 2003
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  advertisement Supply 2A Pulses for GSM Transmission from 500mA USB
  or PCMCIA Ports – Design Note 307
  Dongyan Zhou
  Introduction
  GSM modems have become popular as a wireless data
  transfer solution; however, they frequently require large
  bursts of current that exceed the maximum input current
  available to the voltage regulator. Many can be powered
  from a USB port (4.5V to 5.5V input) or a PCMCIA port
  (3V to 3.6V input), where 3.xV is required to supply the
  RF power amplifier that draws current pulses up to 2A.
  Since the input from the USB or PCMCIA port is current
  limited to 500mA, a high efficiency Buck-Boost converter
  with input current limit provides the best power supply
  solution. High efficiency maximizes the average output
  power, while a bulk output capacitor is used to maintain
  the voltage during the high current pulses. Powering GSM Modems from USB or PCMCIA
  Figure 1 shows a Buck-Boost converter powered from
  USB or PCMCIA. The input current limit is implemented
  by using half of the LT1490A dual micropower op amp.
  The op amp is configured as a current source which
  limits the input current to 500mA. The other half of
  the LT1490A is used as a buffer. Efп¬Ѓciency at the given …

Articles

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  It Just Got Easier to Convert Lithium-Ion Battery Voltage to 3.3V with this Efficient Single Inductor Synchronous Buck-Boost Reg &mdash LT Journal
  PDF, 171 Kb, File published: Mar 1, 2002
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  DESIGN FEATURES It Just Got Easier to Convert LithiumIon Battery Voltage to 3.3V with this
  Efficient Single Inductor Synchronous
  by Mark Jordan
  Buck-Boost Regulator
  Introduction
  One of the most common power supply problems with today’s portable
  devices is generating a regulated voltage that falls somewhere in the middle
  of the full voltage range of the battery.
  For instance, providing a consistent
  3.3V output from a Lithium-Ion (LiIon) battery’s range of 2.5V to 4.2V.
  The most popular topology for solving
  this problem is a SEPIC converter,
  but a SEPIC has some inherent drawbacks, including mediocre efficiency,
  and the requirement of both a coupled
  inductor and a high current flyback
  capacitor. Another solution is a circuit that cascades a boost converter
  with either an LDO or a Buck converter, but this relatively inefficient
  circuit doesn’t fare much better with
  the additional space and money it
  takes for the extra components. LinVIN ear Technology now offers another,
  better solution with the new LTC3440
  Buck-Boost converter, which provides
  the most compact and highest efficiency solution yet—reducing cost, …

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  Versatile Buck-Boost Converter Offers High Efficiency in a Wide Variety of Applications &mdash LT Journal
  PDF, 1.3 Mb, File published: Jun 10, 2005
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  DESIGN FEATURES Versatile Buck-Boost Converter
  Offers High Efficiency in a Wide
  by Dave Salerno
  Variety of Applications
  Introduction L1 5ВµH Miniature hard disk drives are a popular storage medium for MP3 music п¬Ѓles,
  digital photographs and other data
  stowed in the latest portable electronics. Likewise lithium-ion batteries are
  popular for these same devices, which
  presents a minor problem in that mini
  disk drives typically require a 3.3V
  supply, which is right in the middle
  of the lithium-ion battery’s operating
  range (3.0V-to-4.2V). This requires a
  converter that can both step down a
  fully-charged Li-Ion battery and step
  up the same battery as it discharges
  to sub-3.3V levels.
  The LTC3442 is a 1.2A buck-boost
  converter that is ideal for mini disk
  drive applications, and certainly for
  other buck-boost appliations as well.
  The LTC3442 extends battery life with
  95% efп¬Ѓciency and п¬Ѓts into tight spaces …

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Manufacturer's Classification

• Power Management > Switching Regulator > Buck-Boost Regulators > Internal Power Switch Buck-Boost