Datasheet Linear Technology LTC6412

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Design Notes

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  A Low Power, Direct-to-Digital IF Receiver with Variable Gain &mdash DN482
  PDF, 87 Kb, File published: Aug 3, 2010
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  A Low Power, Direct-to-Digital IF Receiver with Variable Gain
  Design Note 482
  Walter Strifler In the face of these problems, basestation receivers
  often require a robust solution that is achieved using
  tried-and-true system methods of downconversion to
  an intermediate frequency (IF) in the range of 70MHz to
  240MHz. Demodulating and decoding the IF signal can
  be performed by various means, but an increasingly
  popular and cost-effective method is direct-to-digital IF
  conversion using the recent generation of high speed,
  low power pipeline data converters available from Linear
  Technology.
  This design note describes a variable gain amplifier plus
  analog-to-digital converter (VGA + ADC) combination
  circuit that preserves the IF receiver dynamic range over
  a 31dB gain adjust range and effectively demodulates and
  digitizes both the I and Q information in a single step.
  The combination LTC В®6412 VGA and LTC2261 14-bit
  ADC circuit subsamples a 140MHz WCDMA IF channel at
  125Msps and provides an equivalent input NF and IP3 that
  rivals some of the best laboratory spectrum analyzers,
  while consuming less than 0.5W of power.
  IF Receiver Performance …

Articles

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  Analog VGA Simplifies Design and Outperforms Competing Gain Control Methods &mdash LT Journal
  PDF, 848 Kb, File published: Sep 1, 2009
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  DESIGN FEATURES L Analog VGA Simplifies Design
  and Outperforms Competing
  by Walter Strifler
  Gain Control Methods
  Introduction
  6 2 19 24 VCC 22 VCC 3
  4
  5 +IN –IN –VG GND 10 11 100
  1000
  FREQUENCY (MHz) vs digital control are also discussed.
  This is followed by a brief introduction
  to the important design and performance features of the LTC6412 along
  with a discussion of a few application
  examples. Analog vs Digital Control
  of VGAs The vast majority of modern communication and imaging equipment
  contains significant digital hardware
  in the form of microprocessors, controllers, memory, data busses and the
  like, so the choice of analog vs digital
  system control would seem to be a
  forgone conclusion in favor of the digi-Figure 2. LTC6412 gain vs frequency over gain
  control range Linear Technology Magazine September 2009 GND GND GND GND EXPOSED
  PAD 8 12 15 18 25 7
  14 5 –V : NEGATIVE …

Model Line

Manufacturer's Classification

• RF & Wireless > Variable Gain Amplifiers > Analog Control VGAs
• Signal Conditioning > Amplifiers > Operational Amplifiers (Op Amps) > High Speed Amplifiers (GBW > 50MHz)
• Signal Conditioning > Amplifiers > Differential Amplifiers > Fully Differential Amplifiers