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LT1074HV LT1076 LT1076 LT1076HV

Application Notes

• Download
  Step Down Switching Regulators &mdash AN35
  PDF, 6.2 Mb, File published: Aug 1, 1989
  Discusses the LT1074, an easily applied step-down regulator IC. Basic concepts and circuits are described along with more sophisticated applications. Six appended sections cover LT1074 circuitry detail, inductor and discrete component selection, current measuring techniques, efficiency considerations and other topics.
  Extract from the document

  Application Note 35
  August 1989
  Step-Down Switching Regulators
  Jim Williams
  lost in this voltage-to-current-to-magnetic п¬Ѓeld-to-current-to-charge-to-voltage conversion. In practice, the
  circuit elements have losses, but step-down efficiency is
  still higher than with inherently dissipative (e.g., voltage
  divider) approaches. Figure 2 feedback controls the basic
  circuit to regulate output voltage. In this case switch ontime (e.g., inductor charge time) is varied to maintain the
  output against changes in input or loading.
  REGULATED
  OUTPUT IN PULSE
  WIDTH
  MODULATOR Figure 1 is a conceptual voltage step-down or “buck”
  circuit. When the switch closes the input voltage appears
  at the inductor. Current flowing through the inductor-capacitor combination builds over time. When the switch
  IN OUT AN35 F01 Figure 1. Conceptual Voltage Step-Down (“Buck”) Circuit opens current flow ceases and the magnetic field around
  the inductor collapses. Faraday teaches that the voltage
  induced by the collapsing magnetic п¬Ѓeld is opposite to the
  originally applied voltage. As such, the inductor’s left side
  heads negative and is clamped by the diode. The capacitors accumulated charge has no discharge path, and a DC
  potential appears at the output. This DC potential is lower
  than the input because the inductor limits current during …

• Download
  LT1074/LT1076 Design Manual &mdash AN44
  PDF, 477 Kb, File published: Sep 1, 1991
  This note discusses the use of the LT1074 and LT1076 high efficiency switching regulators. These regulators are specifically designed for ease of use. This application note is intended to eliminate the most common errors that customers make when using switching regulators as well as offering insight into the inner workings of switching designs. There is an entirely new treatment of inductor design based upon simple mathematical formulas that yield direct results. There are extensive tutorial sections devoted to the care and feeding of the Positive Step- Down (Buck) Converter, the Tapped Inductor Buck Converter, the Positive-to-Negative Converter and the Negative Boost Converter. Additionally, many troubleshooting hints are included as well as oscilloscope techniques, soft-start architectures, and micropower shutdown and EMI suppression methods.
  Extract from the document

  Application Note 44
  September 1991
  LT1074/LT1076 Design Manual
  Carl Nelson
  INTRODUCTION
  The use of switching regulators increased dramatically in
  the 1980’s and this trend remains strong going into the
  90s. The reasons for this are simple; heat and efficiency.
  Today’s systems are shrinking continuously, while simultaneously offering greater electronic “horsepower.” This
  combination would result in unacceptably high internal
  temperatures if low efficiency linear supplies were used.
  Heat sinks do not solve the problem in general because
  most systems are closed, with low thermal transfer from
  “inside” to “outside.”
  Battery-powered systems need high efficiency supplies for
  long battery life. Topological considerations also require
  switching technology. For instance, a battery cannot
  generate an output higher than itself with linear supplies.
  The availability of low cost rechargeable batteries has created a spectacular rise in the number of battery-powered
  systems, and consequently a matching rise in the use of
  switching regulators.
  The LTВ®1074 and LT1076 switching regulators are designed
  specifically for ease of use. They are close to the ultimate …

• Download
  Efficiency and Power Characteristics of Switching Regulator Circuits &mdash AN46
  PDF, 2.6 Mb, File published: Nov 1, 1991
  Efficiency varies for different DC/DC converters. This application note compares the efficiency characteristics of some of the more popular types. Step-up, step-down, flyback, negative-to-positive, and positive-to-negative are shown. Appended sections discuss how to select the proper aluminum electrolytic capacitor and explain power switch and output diode loss calculations.
• Download
  Signal Sources, Conditioners and Power Circuitry Circuits of the Fall, 2004 &mdash AN98
  PDF, 886 Kb, File published: Nov 19, 2004
  Eighteen circuits are presented in this compilation. Signal sources include a voltage controlled current source, an amplitude/frequency stabilized sine wave oscillator, a versatile, 0V to 50V wideband level shift and four sub-nanosecond pulse generators with risetimes as low as 20ps. Five signal conditioners appear; a unique, single positive rail powered amplifier with output to (and below) zero volts, a milliohmmeter, a 0.02% accurate instrumentation amplifier with 120dB CMRR at 125VCM, a 100MHz switch with 5mV control channel feedthrough and a 5V powered, 15ppm linearity quartz stabilized V→F, converter. The power circuits section features a Xenon flashlamp supply, two 5V powered, 0V to 300V DC/DC converters, a fixed 200V output circuit for APD bias, a 100W 0V to 500V, 28V powered converter and a high current paralleling scheme for linear regulators. Two appended sections consider measurement technique and connection practice in sub-nanosecond circuits.
  Extract from the document

  Application Note 98
  November 2004
  Signal Sources, Conditioners and Power Circuitry
  Circuits of the Fall, 2004
  Jim Williams
  Introduction
  Occasionally, we are tasked with designing circuitry for a
  specific purpose. The request may have customer origins
  or it may be an in-house requirement. Alternately, a circuit
  may be developed because its possibility is simply too
  attractive to ignore1. Over time, these circuits accumulate,
  encompassing a wide and useful body of proven capabilities. They also represent substantial effort. These considerations make publication an almost obligatory proposition
  and, as such, a group of circuits is presented here. This is
  not the first time we have displayed such wares and, given
  the encouraging reader response, it will not be the last2.
  Eighteen circuits are included in this latest effort, roughly
  arranged in the categories given in this publication’s title.
  They appear at the next paragraph.
  Voltage Controlled Current Source—Ground Referred
  Input and Output
  A voltage controlled current source with ground referred
  input and output is difficult to achieve. Executions exist,
  but are often cumbersome, involving numerous components. Figure 1’s conceptual design utilizes a differential …

Design Notes

• Download
  No Design Switching Regulator 5V, 5A Buck (Step Down) Regulator &mdash DN48
  PDF, 70 Kb, File published: Aug 1, 1991
  Extract from the document

  advertisement No Design Switching Regulator
  5V, 5A Buck (Step-Down) Regulator – Design Note 48
  Ron Vinsant
  Introduction
  This simple, no design regulator, is a step-down
  DC/DC converter designed to convert an 8V to 40V input
  to a regulated 5V output. The 5V output is capable of
  sourcing up to 5A of output current.
  This converter is based on the Linear Technology
  LTВ®1074 switching regulator IC. This device needs only
  a few external parts to make up a complete regulator
  including thermal protection and current limit. This
  design uses off-the-shelf parts for low cost and easy
  availability of components. Specifications for the circuit
  are in Table 1.
  Circuit Description
  Figure 1 shows the schematic of the circuit. For the
  purpose of this explanation assume that the output
  is at a constant +5V DC and that the input voltage is
  greater than +8V DC.
  At intervals of ≈10μs (100kHz) the control portion of the
  LT1074 turns on the switch transistor between the VIN
  and VSW pins impressing a voltage across the inductor, …

• Download
  No Design Switiching Regulator 5V Buck-Boost (Positive to Negative) Regulator &mdash DN49
  PDF, 71 Kb, File published: Sep 1, 1991
  Extract from the document

  advertisement No Design Switching Regulator
  5V Buck-Boost (Positive-to-Negative) Regulator – Design Note 49
  Ron Vinsant
  Introduction
  This simple, no design regulator, operates with an input
  between 4.5V DC and 40V DC. It provides a –5V output
  at a maximum output current of 1A to 3A depending
  on input voltage.
  This converter is based on the Linear Technology
  LTВ®1074 switching regulator IC. This device needs only
  a few external parts to make up a complete regulator
  including thermal protection and current limit. This
  design uses off-the-shelf parts for low cost and easy
  availability of components. Specifications for the circuit
  are in Table 1.
  Circuit Description
  Figure 1 shows the schematic of the circuit. For the
  purpose of this explanation assume that the output
  is at a constant –5V DC and that the input voltage is
  greater than +4.5V DC.
  At intervals of ≈10μs (100kHz) the control portion of the
  LT1074 turns on the switch transistor between the VIN
  and VSW pins impressing a voltage across the inductor, L1. This causes current to build up in the inductor. …

Model Line

Manufacturer's Classification

• Power Management > Switching Regulator > Step-Down (Buck) Regulators > High Input Voltage Buck | Internal Power Switch Buck
• Power Management > Switching Regulator > Inverting Regulators

Other Names:

LT1074CT7PBF, LT1074CT7 PBF