Datasheet Linear Technology LT1394

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Application Notes

• Download
  High Voltage, Low Noise, DC/DC Converters &mdash AN118
  PDF, 2.6 Mb, File published: Mar 28, 2008
  Photomultipliers (PMT), avalanche photodiodes (APD), ultrasonic transducers, capacitance microphones, radiation detectors and similar devices require high voltage, low current bias. Additionally, the high voltage must be pristinely free of noise; well under a millivolt is a common requirement with a few hundred microvolts sometimes necessary. Normally, switching regulator configurations cannot achieve this performance level without employing special techniques. One aid to achieving low noise is that load currents rarely exceed 5mA. This freedom permits output filtering methods that are usually impractical.
  Extract from the document

  Application Note 118
  March 2008
  High Voltage, Low Noise, DC/DC Converters
  A Kilovolt with 100 Microvolts of Noise
  Jim Williams This publication describes a variety of circuits featuring
  outputs from 200V to 1000V with output noise below 100ВµV
  measured in a 100MHz bandwidth. Special techniques
  enable this performance, most notably power stages
  optimized to minimize high frequency harmonic content.
  Although sophisticated, all examples presented utilize
  standard, commercially available magnetics—no custom
  components are required. This provision is intended to
  assist the user in quickly arriving at a produceable design.
  Circuits and their descriptions are presented beginning
  with the next ink.
  BEFORE PROCEEDING ANY FURTHER, THE READER
  IS WARNED THAT CAUTION MUST BE USED IN THE
  CONSTRUCTION, TESTING AND USE OF THE TEXT’S
  CIRCUITS. HIGH VOLTAGE, LETHAL POTENTIALS ARE
  PRESENT IN THESE CIRCUITS. EXTREME CAUTION
  MUST BE USED IN WORKING WITH, AND MAKING
  CONNECTIONS TO, THESE CIRCUITS. REPEAT: THESE
  CIRCUITS CONTAIN DANGEROUS, HIGH VOLTAGE …

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  A Seven-Nanosecond Comparator for Single Supply Operation &mdash AN72
  PDF, 882 Kb, File published: May 1, 1998
  AN72 is an extensive discussion of the causes and cures of problems in very high speed comparator circuits. A separate applications section uses the 7ns LT1394 in V-to-F converters, crystal oscillators, clock skew generators, triggers, sampling configurations and a nanosecond pulse stretcher. Appendices cover related topics.
  Extract from the document

  Application Note 72
  May 1998
  A Seven-Nanosecond Comparator
  for Single Supply Operation
  Guidance for Putting Civilized Speed to Work
  Jim Williams INTRODUCTION
  In 1985 Linear Technology Corporation introduced the
  LT В®1016 Comparator. This device was the first readily
  usable, high speed TTL comparator. Previous ICs were
  either too slow or unstable, preventing widespread
  acceptance. The LT1016 was, and is, a highly successful
  product.
  Recent technology trends have emphasized low power,
  single supply operation. The LT1016, although capable of
  such operation, does not include ground in its input range.
  As such, it must be biased into its operating common
  mode range for practical single supply use. A new device,
  the LT1394, maintains the speed and application civility of
  its predecessor while including ground in its input operating range. Additionally, the new comparator is faster and
  pulls significantly lower operating current than the LT1016.
  This publication borrows shamelessly from earlier LTC
  efforts, while introducing new material.1 It approximates,
  affixes, appends, abridges, amends, abbreviates, abrogates, ameliorates and augments the previous work.2 …

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  30 Nanosecond Settling Time Measurement for a Precision Wideband Amplifier &mdash AN79
  PDF, 624 Kb, File published: Sep 5, 1999
  AN79 modifies methods presented in AN74, permitting verification of 30 nanosecond amplifier settling times to 0.1% resolution. The sampling-based technique used is detailed and results presented. Appendices cover oscilloscope overdrive issues, construction of a subnanosecond rise time pulse generator, amplifier compensation, circuit construction and calibration procedures.
  Extract from the document

  Application Note 79
  September 1999
  30 Nanosecond Settling Time Measurement for a
  Precision Wideband Amplifier
  Quantifying Prompt Certainty
  Jim Williams Introduction
  Instrumentation, waveform generation, data acquisition,
  feedback control systems and other application areas
  utilize wideband amplifiers. New components (see page 2
  “A Precision Wideband Dual Amplifier with 30ns Settling
  Time”) have introduced precision while maintaining high
  speed operation. The amplifier’s DC and AC specifications
  approach or equal previous devices at significantly lower
  cost while saving power.
  Settling Time Defined
  Amplifier DC specifications are relatively easy to verify.
  Measurement techniques are well understood, albeit often
  tedious. AC specifications require more sophisticated
  approaches to produce reliable information. In particular,
  amplifier settling time is extraordinarily difficult to determine. Settling time is the elapsed time from input application until the output arrives at and remains within a
  specified error band around the final value. It is usually
  specified for a full-scale transition. Figure 1 shows that
  settling time has three distinct components. The delay …

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  Low Noise Varactor Biasing with Switching Regulators: Vanquishing Villainous Vitiators Vis-Г -Vis Vital Varactors &mdash AN85
  PDF, 490 Kb, File published: Aug 1, 2000
  Telecommunication, satellite links and set-top boxes all require tuning a high frequency oscillation. The actual tuning element, a varactor diode, requires high voltage bias for operation. The high voltage bias must be free of noise to prevent unwanted oscillator outputs. This publication details a method for generating noise free high voltage from low voltage inputs using switching regulators. Spurious oscillator outputs are below -90dBc. Suggested circuit and layout information is included. Appendices cover varactor diode theory and performance verification techniques.
  Extract from the document

  Application Note 85
  August 2000
  Low Noise Varactor Biasing with Switching Regulators
  Vanquishing Villainous Vitiators Vis-Г -Vis Vital Varactors
  Jim Williams and David Beebe
  INTRODUCTION “hyperabrupt” devices. Response modification is possible,
  with compromises in performance, particularly with regard
  to linearity and sensitivity.2 Telecommunication, satellite links and set-top boxes all
  require tuning a high frequency oscillator. The actual
  tuning element is a varactor diode, a 2-terminal device that
  changes capacitance as a function of reverse bias voltage.1 The oscillator is part of a frequency synthesizing
  loop, as detailed in Figure 1. A phase locked loop (PLL)
  compares a divided down representation of the oscillator
  with a frequency reference. The PLL’s output is level
  shifted to provide the high voltage necessary to bias the
  varactor, which closes a feedback loop by voltage tuning
  the oscillator. This loop forces the voltage controlled
  oscillator (VCO) to operate at a frequency determined by
  the frequency reference and the divider’s division ratio. Note 1. Theoretical considerations of varactor diodes are treated in
  Appendix A, “Zetex Variable Capacitance Diodes,” guest written by Neil
  Chadderton of Zetex.
  Note 2. The reader is again referred to Appendix A for in-depth discussion
  of varactor diodes. …

Design Notes

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  A Seven Nanosecond Comparator for Single-Supply Operation &mdash DN185
  PDF, 86 Kb, File published: Aug 1, 1998
  Extract from the document

  A Seven Nanosecond Comparator for Single-Supply
  Operation – Design Note 185
  Jim Williams
  The LT®1394—An Overview
  A new ultrahigh speed, single-supply comparator,
  the LT1394, features TTL-compatible complementary
  outputs and 7ns response time. Other capabilities
  include a latch pin and good DC input characteristics
  (see Figure 1). The LT1394’s outputs directly drive all
  5V families, including the higher speed ASTTL, FAST
  and HC parts. Additionally, TTL outputs make the device
  easier to use in linear circuit applications where ECL
  output levels are often inconvenient.
  A substantial amount of design effort has made the
  LT1394 relatively easy to use. It is much less prone to
  oscillation and other vagaries than some slower comparators, even with slow input signals. In particular,
  the LT1394 is stable in its linear region. Additionally,
  output-stage switching does not appreciably change
  power supply current, further enhancing stability.
  Finally, current consumption is far lower than that of
  previous devices. These features make the 200GHz
  gain bandwidth LT1394 considerably easier to apply
  than other fast comparators. 4Г— NTSC Subcarrier Tunable Crystal Oscillator …

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  Rail-to-Rail I/O and 2.4V Operation Allow UltraFast Comparators to be Used on Low Voltage Supplies &mdash DN248
  PDF, 105 Kb, File published: Jan 1, 2001
  Extract from the document

  Rail-to-Rail I/O and 2.4V Operation Allow UltraFast Comparators to be Used on Low Voltage Supplies
  Design Note 248
  Glen Brisebois
  The new LTВ®1711 to LT1714 family of UltraFastв„ў
  comparators have full differential rail-to-rail inputs and
  outputs and operate down to 2.4V, allowing unfettered
  application on low supply voltages. The LT1711 (single)
  and LT1712 (dual) are specified at 4.5ns of propagation
  delay and 100MHz toggle frequency. The lower power
  LT1713 (single) and LT1714 (dual) are specified at 7ns
  of propagation delay and 65MHz toggle frequency. All
  of these comparators are fully equipped to support
  multiple supply applications and have Latch Enable
  (LE) pins and complementary outputs like the popular
  LT1016, LT1116, LT1671 and LT1394. They are available in MSOP and SSOP packages, fully specified
  over commercial and industrial temperature ranges
  on 2.7V, 5V and В±5V supplies.
  Simultaneous Full Duplex 75Mbaud Interface
  with Only Two Wires
  The circuit of Figure 1 shows a simple, fully bidirectional, differential 2-wire interface that gives good
  results to 75Mbaud, using the lower power LT1714.
  Eye diagrams under conditions of unidirectional and
  bidirectional communication are shown in Figures 2 …

Articles

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  New UltraFast Comparators: Rail-to-Rail Inputs and 2.4V Operation Allow Use on Low Supplies &mdash LT Journal
  PDF, 194 Kb, File published: Feb 1, 2001
  Extract from the document

  DESIGN FEATURES New UltraFast Comparators: Rail-toRail Inputs and 2.4V Operation Allow
  Use on Low Supplies
  by Glen Brisebois
  Introduction
  The new LT1711 family of UltraFast
  comparators has fully differential railto-rail inputs and outputs and
  operates on supplies as low as 2.4V,
  allowing unfettered application on low
  voltages. The LT1711 (single) and
  LT1712 (dual) are specified at 4.5ns
  of propagation delay and 100MHz
  toggle frequency. The low power
  LT1713 (single) and LT1714 (dual)
  are specified at 7ns of propagation
  delay and 65MHz toggle frequency.
  All of these comparators are fully
  equipped to support multiple-supply
  applications, and have latch-enable
  pins and complementary outputs like
  the popular LT1016, LT1671 and
  LT1394. They are available in MSOP
  and SSOP packages, fully specified
  over commercial and industrial temperature ranges on 2.7V, 5V and В±5V …

• Download
  A 7ns, 6mA, Single-Supply Comparator Fabricated on Linear &mdash LT Journal
  PDF, 271 Kb, File published: May 1, 1998
  Extract from the document

  DESIGN FEATURES A 7ns, 6mA, Single-Supply
  Comparator Fabricated on Linear’s
  6GHz Complementary Bipolar Process
  by Jim Williams and Brian Hamilton
  Introduction
  The LT1394 is an ultrafast (7ns), low
  power (6mA), single-supply comparator designed to operate on either 5V
  or В±5V supplies. It has a maximum
  offset voltage of 2.5mV, complementary TTL compatible outputs and
  output latch capability. The LT1394
  is the first product made with Linear
  Technology’s 6GHz complementary
  bipolar technology. This fine-line
  geometry process results in a product
  with dramatically improved speed and
  power compared to industry-standard
  comparators developed in slower NPNonly technologies.
  These features combine to make
  the LT1394 well suited for applicaVCC I1 I2 I3 I4 D15
  VCC VEE D2 R4 tions such as high performance NTSC
  crystal oscillators, single-supply voltage-to-frequency converters and high
  speed, high accuracy level detectors.
  The LT1394 is offered in SO-8 and is …

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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 …

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Manufacturer's Classification

• Signal Conditioning > Comparators > High Speed Comparators