Datasheet Linear Technology LT1964EDD#PBF

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Design Notes

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  Ultralow Noise Switching Power Supplies Simplify EMI Compliance &mdash DN316
  PDF, 94 Kb, File published: Jul 2, 2003
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  advertisement Ultralow Noise Switching Power Supplies Simplify
  EMI Compliance – Design Note 316
  David Canny
  Introduction
  Most electronic products must pass electromagnetic
  interference (EMI) compliance tests—such as the FCC
  Part 15 rules in the US—before they can be released
  into the market. When a company’s product fails EMI
  compliance tests, the company loses control of the
  development process, shipping dates begin to slip,
  projected revenues diminish and expenses start piling
  up. Furthermore, excessive noise can interfere with
  sensitive electronics within the product itself. So it is
  essential that electronic products are designed from
  the beginning with EMI attenuation in mind. Often the
  EMI compliance problem lies in the product’s switching power supply. In these cases, the best solution is
  prevention by using an ultralow noise switching power
  supply in the initial design, rather than adding shields
  and п¬Ѓlters to the product after the fact. Circuit Description
  Figure 1 shows the LTВ®3439, one of several low noise
  switchers available from Linear Technology. Ultralow
  noise and low EMI are achieved by controlling both
  the output switch voltage and current slew rates. This …

Articles

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  Micropower Negative LDO Provides a Quiet Output in SOT-23 &mdash LT Journal
  PDF, 75 Kb, File published: Dec 1, 2001
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  DESIGN FEATURES Micropower Negative LDO Provides a
  by Todd Owen
  Quiet Output in SOT-23
  Introduction Taking the Flip Side
  A wide choice of regulators is available for providing a low noise positive
  supply voltage. Now, it is possible to
  provide a similar level of performance
  for a negative supply. Figure 1 shows
  a typical application for the LT1964,
  a new negative low dropout regulator
  in a 5-lead SOT-23 package. The
  LT1964 provides the lowest noise
  available from any negative LDO and
  it is a micropower device. The LT1964
  incorporates features that make it
  useful for a variety of applications. It
  is stable with a wide range of output
  capacitors with an ESR in the range
  of only a few milliohms up to 3Ω.
  Small ceramic capacitors can be used
  without the addition of ESR as is
  common with other regulators. The
  output capacitor can be as low as 1ВµF …

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  A Simple Solution to Low Noise, Isolated Power Conversion &mdash LT Journal
  PDF, 181 Kb, File published: Nov 1, 2002
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  DESIGN IDEAS A Simple Solution to Low Noise,
  Isolated Power Conversion by Tom Sheehan
  Introduction
  the turns ratio. Rectifiers on the secondary side generate the DC output
  voltage. The output capacitor is for
  hold up and filtering. If required, an
  additional inductor and capacitor can
  be added to reduce the output noise
  even further.
  Control of the voltage and current
  slew rate is maintained via two control loops. One loop controls the
  output switch dV/dt and the other
  loop controls the output switch dI/dt.
  Output slew control is achieved by
  comparing the two currents generated by these slewing events to a
  current set by the external resistor
  RSL.
  The frequency of the internal oscillator can be set from 20kHz to 250kHz
  with an external resistor and capacitor, RT and CT. Each output switch is
  driven at half the frequency of the
  oscillator. The SYNC pin can be used
  to synchronize the switching to an
  external clock. A SHDN pin can be …

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Manufacturer's Classification

• Power Management > LDO Linear Regulators > Negative Linear Regulators (LDO)

Other Names:

LT1964EDDPBF, LT1964EDD PBF