Datasheet Linear Technology LTC1682IMS8#PBF

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Design Notes

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  Tiny Regulators Drive White LED Backlights &mdash DN231
  PDF, 76 Kb, File published: May 1, 2001
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  Tiny Regulators Drive White LED Backlights – Design Note 231
  Dave Kim
  Introduction
  The emergence of color LCD displays in handheld
  information appliances has created the need for a
  small, bright white backlight. Fortunately, the recent
  commercialization of high intensity white LEDs provides
  the perfect solution. These tiny LEDs are capable of
  delivering ample white light without the fragility problems and costs associated with fluorescent backlights
  commonly used in notebook computers. However, they
  do pose a problem—the forward voltage of white LEDs
  can be as high as 4V, precluding powering them directly
  from a single lithium-ion cell.
  This Design Note describes several different circuits that
  may be used to boost and regulate the Li-Ion battery
  voltage to power white LEDs. These circuits provide
  sufficient power to drive multiple white LEDs and are
  small enough to easily п¬Ѓt within cellular telephones and
  handheld computers. VIN
  3V TO
  4.2V LTC1754-5
  C3
  10ОјF …

Articles

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  Low Noise Boost VCO Power Supply for Portable Applications &mdash LT Journal
  PDF, 167 Kb, File published: Sep 1, 1999
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  DESIGN IDEAS Low Noise Boost VCO Power Supply
  for Portable Applications
  by Ted Henderson
  Introduction
  Many portable RF products use voltage controlled oscillators (VCOs) to
  generate the RF carrier frequency.
  These applications often require low
  noise VCO power supply voltages that
  are greater than the primary battery
  supply. A DC/DC converter powering
  a low noise linear regulator is often
  used. Unfortunately, there are several disadvantages to this solution.
  The DC/DC converter tends to produce noise that may not be rejected
  by the regulator, resulting in regulator output noise far greater than the
  thermal noise levels. The linear regulator may require a large output compensation capacitor with specific
  ESR requirements. The board area
  for both devices and support components can be large. The LTC1682
  charge pump DC/DC voltage converter has been designed to minimize
  these issues. The charge pump and
  linear regulator have been mutually
  optimized for minimum regulator output noise. The linear regulator was
  designed to operate with several different types of output capacitors
  including small, low value, low ESR …

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Manufacturer's Classification

• Power Management > Inductorless (Charge Pump) DC/DC Converters > Regulated Step-Up Charge Pumps

Other Names:

LTC1682IMS8PBF, LTC1682IMS8 PBF