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LT1721 LT1721

Application Notes

• Download
  Circuitry for Signal Conditioning and Power Conversion &mdash AN75
  PDF, 508 Kb, File published: Mar 1, 1999
  This publication includes designs for data converters and signal conditioners, transducer circuits, crystal oscillators and power converters. Wideband and micropower circuitry receive special attention. Tutorials on micropower design techniques and parasitic effects of test equipment are included.
  Extract from the document

  Application Note 75
  March 1999
  Circuitry for Signal Conditioning and
  Power Conversion
  Designs From a Once Lazy Sabbatical
  Jim Williams
  Introduction
  Linear Technology has a sabbatical program. Every five
  years employees are granted sabbatical leave, which may
  last up to six weeks. You have 18 months from each five
  year employment anniversary to take the leave. Sabbatical
  is fully company paid and has no restrictions. The time is
  yours to do with as you please.
  People exercise all degrees of freedom with their sabbaticals. They go sailing, they go to South Sea islands, they ski
  some mountain nobody ever heard of, they trek in Nepal.
  Houses get fixed, cars restored and children played with.
  For my third sabbatical I resolved to do absolutely nothing.
  For the first time in my life I was really tired, and I knew it.
  A six week rest sounded just fine. I’d walk the dog and
  spend time with my wife and son. That’s it. No transistors,
  no resistors, no op amps and, above all, no writing. I was
  so written out the thought of picking up a pencil produced
  an instant headache. …

Design Notes

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  Precision LVDT Signal Conditioning Using Direct RMS to DC Conversion &mdash DN362
  PDF, 75 Kb, File published: Mar 23, 2005
  Extract from the document

  Precision LVDT Signal Conditioning Using Direct RMS to DC
  Conversion – Design Note 362
  Cheng-Wei Pei
  lowpass filtering of the rectified sine wave. However,
  the precision of the demodulation method depends on
  the accuracy of the phase adjustment. In addition, there
  are losses associated with demodulation, which usually
  involve switches and the associated charge injection
  and timing jitter. It is difficult to achieve 12-bit precision
  under these circumstances. Introduction
  Linear variable differential transformers (LVDTs) are
  theoretically infinite-resolution displacement measurement devices. An LVDT operates by comparing the
  magnetic flux coupled into two transformer secondary
  windings to determine the displacement of a moving
  transformer core. A low distortion sine wave acts as
  the input. The amplitude and phase of the output signal across the two secondary windings determine the
  distance and polarity of the LVDT core with respect to
  the center.
  Proper signal conditioning circuitry allows extremely
  precise measurements in demanding applications,
  such as in production manufacturing, fluid level measurements and structural/strain testing. One common
  application is to use an LVDT at the end of a Bourdon
  tube to measure minute changes in system or barometric pressure. A better approach to LVDT signal conditioning is shown …

Articles

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  4.5ns Dual-Comparator-Based Crystal Oscillator has 50% Duty Cycle and Complementary Outputs &mdash LT Journal
  PDF, 194 Kb, File published: Aug 1, 1998
  Extract from the document

  DESIGN IDEAS
  ing spikes ruin an otherwise clean
  output.
  Efficiency of the circuit is detailed
  in Figure 5. Efficiency reaches 73%
  at a 50mA load, and is above 70% at
  a 200mA load. Larger inductors with
  less copper resistance can be used to
  increase efficiency, although such
  inductors are more expensive than
  the Murata units specified. 90 80
  EFFICIENCY (%) low noise that can be achieved with a
  ceramic capacitor may be corrupted
  by noise spikes if proper layout practice is not followed. To illustrate this
  point, output and switch waveforms
  from Figure 1’s circuit, with a 10µ F
  ceramic output capacitor and 200mA
  load, but with D1’s cathode arbitrarily connected to the ground plane,
  are shown in Figure 4. 60mV switch-70 60 50 40
  10
  30
  100
  LOAD CURRENT (mA) 3 300 1610 TA02 …

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  A 4.5ns, 4mA, Single-Supply, Dual Comparator Optimized for 3V/5V Operation &mdash LT Journal
  PDF, 287 Kb, File published: Nov 1, 1998
  Extract from the document

  DESIGN FEATURES A 4.5ns, 4mA, Single-Supply,
  Dual Comparator Optimized for
  by Joseph G. Petrofsky
  3V/5V Operation
  Introduction NONLINEAR STAGE The LT1720 is an UltraFastв„ў (4.5ns),
  low power (4mA/comparator), singlesupply, dual comparator designed to
  operate on a single 3V or 5V supply.
  These comparators feature internal
  hysteresis, making them easy to use,
  even with slowly moving input signals. The LT1720 is fabricated in
  Linear Technology’s 6GHz complementary bipolar process, resulting
  in unprecedented speed for its low
  power consumption. Table 1 summarizes the LT1720’s perfor mance
  specifications.
  The LT1720 is offered in SO-8,
  with just three pins per comparator
  plus power and ground. For a
  full-featured, 7ns, single-supply comparator with dual complementary
  outputs and internal latch, the
  LT1394 is available from this same
  high speed process.
  These fast, small, low power comparators are versatile building blocks
  for a variety of high speed, singlesupply applications, such as clock …

• Download
  Comparator Circuit Provides Automatic Shutdown of the LT1795 High Speed ADSL Power Amplifier &mdash LT Journal
  PDF, 154 Kb, File published: Sep 1, 1999
  Extract from the document

  DESIGN IDEAS Comparator Circuit Provides Automatic
  Shutdown of the LT1795 High Speed
  ADSL Power Amplifier
  by Tim Regan
  Introduction
  Data transmission standards such
  as HDSL2, ADSL (both Full Rate and
  G.Lite) and VDSL (collectively known
  as xDSL) require the combined speed,
  output power and dynamic range
  capabilities of the LT1795 to drive the
  telephone line. In a typical data communications installation, in both the
  telephone central office and office
  building sites, hundreds of telephonewire pairs are brought together into a
  line multiplexer. These multiplexers
  compact the individual line driver and
  receiver circuits to save space. Eight
  lines per PC card are often implemented. This tight partitioning raises
  the challenges of both power and heat
  management in each installation.
  A simple comparator circuit can be
  used to monitor the activity of an
  individual phone line and completely …

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Manufacturer's Classification

• Signal Conditioning > Comparators > High Speed Comparators