Datasheet Linear Technology LT1223

Datasheets

Prices

Packaging

Parametrics

Eco Plan

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 …

• Download
  High Speed Amplifier Techniques &mdash AN47
  PDF, 5.3 Mb, File published: Aug 1, 1991
  This application note, subtitled "A Designer's Companion for Wideband Circuitry," is intended as a reference source for designing with fast amplifiers. Approximately 150 pages and 300 figures cover frequently encountered problems and their possible causes. Circuits include a wide range of amplifiers, filters, oscillators, data converters and signal conditioners. Eleven appended sections discuss related topics including oscilloscopes, probe selection, measurement and equipment considerations, and breadboarding techniques.
  Extract from the document

  Application Note 47
  August 1991
  High Speed Amplifier Techniques
  A Designer’s Companion for Wideband Circuitry
  Jim Williams PREFACE
  This publication represents the largest LTC commitment
  to an application note to date. No other application note
  absorbed as much effort, took so long or cost so much.
  This level of activity is justified by our belief that high speed
  monolithic amplifiers greatly interest users.
  Historically, monolithic amplifiers have represented packets of inexpensive, precise and controllable gain. They
  have partially freed engineers from the constraints and
  frustrations of device level design. Monolithic operational
  amplifiers have been the key to practical implementation
  of high level analog functions. As good as they are, one
  missing element in these devices has been speed.
  Devices presently coming to market are addressing monolithic amplifiers’ lack of speed. They bring with them the
  ease of use and inherent flexibility of op amps. When Philbrick Researches introduced the first mass produced
  op amp in the 1950’s (K2-W) they knew it would be used.
  What they couldn’t possibly know was just how widely,
  and how many different types of applications there were.
  As good a deal as the K2-W was (I paid $24.00 for mine or rather, my father did), monolithic devices are far better.
  The combination of ease of use, economy, precision and …

• Download
  Video Circuit Collection &mdash AN57
  PDF, 559 Kb, File published: Jan 2, 1994
  AN57, the Video Circuit Collection, features a variety of video circuits designed at LTC. The LT1204 70MHz multiplexer is featured in a number of circuits which require excellent video isolation from channel to channel. High speed voltage and current feedback amplifiers are highlighted throughout the section on video processing circuits. There is a section on applying Current Feedback Amplifiers (CFAs) and a number of articles taken from the Linear Technology magazine.
  Extract from the document

  Application Note 57
  January 1994
  Video Circuit Collection
  Jon Munson and Frank Cox
  INTRODUCTION
  Even in a time of rapidly advancing digital image processing, analog video signal processing still remains eminently
  viable. The video A/D converters need a supply of properly
  amplified, limited, DC restored, clamped, clipped, contoured, multiplexed, faded and filtered analog video before
  they can accomplish anything. After the digital magic is
  performed, there is usually more amplifying and п¬Ѓltering
  to do as an adjunct to the D/A conversion process, not to mention all those pesky cables to drive. The analog way
  is often the most expedient and efficient, and you don’t
  have to write all that code.
  The foregoing is only partly in jest. The experienced engineer
  will use whatever method will properly get the job done;
  analog, digital or magic (more realistically, a combination
  of all three). Presented here is a collection of analog video
  circuits that have proven themselves useful. CIRCUIT INDEX
  I. Video Amplifier Selection Guide . 2 II. Video Cable Drivers . 3
  AC-Coupled Video Drivers . 3
  DC-Coupled Video Drivers . 4
  Clamped AC-Input Video Cable Driver . 5
  Twisted-Pair Video Driver and Receiver . 5 III. Video Processing Circuits . 6 …

• Download
  A Monolithic Switching Regulator with 100ВµV Output Noise &mdash AN70
  PDF, 1.7 Mb, Language: en, File published: Oct 1, 1997
  This publication details circuitry and applications considerations for the LT1533 low noise switching regulator. Eleven DC/DC converter circuits are presented, some offering <100µV output noise in a 100MHz bandwidth. Tutorial sections detail low noise DC/DC design, measurement, probing and layout techniques, and magnetics selection.
  Extract from the document

  Application Note 70
  October 1997
  A Monolithic Switching Regulator with 100ВµV Output Noise
  “Silence is the perfectest herald of joy .”
  Jim Williams INTRODUCTION
  Size, output flexibility and efficiency advantages have
  made switching regulators common in electronic apparatus. The continued emphasis on these attributes has
  resulted in circuitry with 95% efficiency that requires
  minimal board area. Although these advantages are welcome, they necessitate compromising other parameters. back to the driving source (“reflected” noise) and it is
  radiated. The multiple transmission paths combine with
  the high frequency content to make noise suppression
  difficult. Unconscionable amounts of bypass capacitors,
  ferrite beads, shields, Mu-metal and aspirin have been
  expended in attempts to ameliorate noise-induced effects. Switching Regulator “Noise”
  Something commonly referred to as “noise” is a primary
  concern. The switched mode power delivery that permits
  the aforementioned advantages also creates wideband
  harmonic energy. This undesirable energy appears as
  radiated and conducted components commonly labeled
  as “noise.” Actually, switching regulator output “noise” is
  not really noise at all, but coherent, high frequency residue
  directly related to the regulatorвЂ^TMs switching.1 Figure 1
  shows typical switching regulator output noise. Two distinct characteristics are present. The slow, ramping output …

Design Notes

• Download
  A Precision Wideband Current Probe for LCD Backlight Measurement &mdash DN101
  PDF, 93 Kb, File published: Apr 1, 1995
  Extract from the document

  A Precision Wideband Current Probe for LCD Backlight
  Measurement – Design Note 101
  Jim Williams
  Evaluation and optimization of Cold Cathode Fluorescent
  Lamp (CCFL) performance requires highly accurate
  AC current measurement. CCFLs, used to backlight
  LCD displays, typically operate at 30kHz to 70kHz
  with measurable harmonic content into the low MHz
  region1. Accurate determination of RMS operating current is important for electrical and emissivity efficiency
  computations and to ensure long lamp life. Additionally,
  it is desirable to be able to perform current measurements in the presence of high common-mode voltage
  (>1000VRMS). This capability allows investigation and
  quantification of display and wiring induced losses,
  regardless of their origins in the lamp drive circuitry. operating at a gain of about 3.75. No impedance matching is required due to the probe’s low output impedance
  termination. Additional amplifiers provide distributed
  gain, maintaining wide bandwidth with an overall gain
  of about 200. The individual amplifiers avoid any possible crosstalk-based error that could be introduced
  by a monolithic quad amplifier. D1 and Rx are selected
  for polarity and value to trim overall amplifier offset.
  The 100О© trimmer sets gain, п¬Ѓxing the scale factor.
  The output drives a thermally-based, wideband RMS
  voltmeter. In practice, the circuit is built into a 2.25" Г—
  1" Г— 1" enclosure which is directly connected, via BNC …

• Download
  Current Feedback Amplifier Do's and Don'ts &mdash DN46
  PDF, 167 Kb, File published: Apr 1, 1991
  Extract from the document

  Current Feedback Amplifier “Do’s and Don’ts” – Design Note 46
  William H. Gross
  Introduction
  The introduction of current feedback amplifiers, such as
  the LT®1223, has significantly increased the designer’s
  ability to solve difficult high speed amplifier problems.
  The current feedback architecture has very high slew rate
  and the small-signal bandwidth is fairly constant for all
  gains. Current feedback amplifiers are used in broadcast
  video systems, radar systems, IF and RF stages, RGB
  distribution systems and many other high speed circuits.
  As with any new circuit, there are several new rules that
  must be kept in mind to prevent problems. Because current
  feedback amplifiers act very much the same as regular op
  amps, it is important to note the differences and show how
  some standard op amp circuits should be implemented.
  The most important thing to remember about current
  feedback amplifiers is that the impedance at the inverting (negative) input sets the bandwidth and therefore the
  stability of the amplifier. It should be resistive, not capacitive. To slow the amplifier down, increase the resistance
  driving the inverting input. If the amplifier peaks too much
  due to capacitive loading or anything else, increase the
  value of the feedback resistors.
  The best way to demonstrate how to use current feedback …

• Download
  High Frequency Amplifier Evaluation Board &mdash DN50
  PDF, 121 Kb, File published: Jan 1, 1991
  Extract from the document

  High Frequency Amplifier Evaluation Board – Design Note 50
  Mitchell Lee
  Introduction
  Demo board DC009 is designed to simplify the evaluation
  of high speed operational amplifiers. It includes both an
  inverting and non-inverting circuit, and pads are provided
  to allow the use of board-mounted BNC or SMA connectors.
  The two circuits are independent, with the exception of
  shared power supply and ground connections. High Speed Layout Techniques grounds are still separated. For example, the termination
  resistors (R3 and R7) and the gain-setting resistor (R1)
  are grounded in the vicinity of the input connector. Supply
  bypass capacitors (C1, C2, C4, C5, C7, C8, C9, and C10)
  are returned to ground in the vicinity of the output
  connectors. Optional Components Layout is a primary contributor to the performance of any
  high speed amplifier. Poor layout techniques adversely
  affect the behavior of a finished circuit. Several important
  layout techniques, all used in demo board DC009, are
  described below: The circuit board is designed to accommodate standard 8pin miniDIP, single operational amplifiers, such as the
  LT1190 and LT1220 families. Both voltage and current
  feedback types can be used. Pins 1, 5, and 8 are outfitted
  with pads for use in adjusting DC offsets, compensation
  or, in the case of the LT1223 and LT1190/1/2, for shutting
  down the amplifier. Top Side Ground Plane: The primary task of a ground …

• Download
  Video Circuits Collection &mdash DN57
  PDF, 79 Kb, File published: Apr 1, 1992
  Extract from the document

  Video Circuits Collection – Design Note 57
  William H. Gross
  Introduction
  This note shows how to make several different video
  circuits using high speed op amps. All of these circuits
  work with composite, RGB and monochrome video.
  For best results, bypass the power supply pins of
  these amplifiers with 1μF to 10μF tantalum capacitors
  in parallel with 0.01ОјF disc capacitors. It is important
  to terminate both ends of video cables to preserve
  frequency response. When properly terminated, the
  cable looks like a resistive load of 150О©.
  Lots of Inputs Video MUX Cable Driver (LT1227) Multiplex Amplifiers
  Often it is desirable to select one of several signals to
  send down a cable. Connecting the outputs of several
  amplifiers together and using the amplifier’s shutdown
  pin to disable all but one accomplishes this goal. The
  LTВ®1190, LT1191, LT1192, and LT1193 are shutdown by
  pulling pin 5 to the negative supply.
  The LT1223 and LT1227 current feedback amplifiers are
  shutdown by pulling Pin 8 to ground. During normal
  operation Pin 8 is open and at the positive supply potential. An easy way to interface Pin 8 to logic is with
  a logic level N-channel FET or a 74C906 (open-drain …

Model Line

Manufacturer's Classification

• Signal Conditioning > Amplifiers > Operational Amplifiers (Op Amps) > High Speed Amplifiers (GBW > 50MHz) | Current Feedback Amplifiers | High Voltage Amplifiers (>12V)