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Crystal oscillator emulator

  • US 7,760,036 B2
  • Filed: 04/03/2007
  • Issued: 07/20/2010
  • Est. Priority Date: 10/15/2002
  • Status: Active Grant
First Claim
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1. An integrated circuit comprising:

  • a film bulk acoustic resonator (FBAR) circuit that generates a reference frequency;

    a temperature sensor that senses a temperature of said integrated circuit;

    memory that stores calibration parameters and that selects at least one of said calibration parameters as a function of said sensed temperature;

    a phase locked loop module that receives said reference signal, that comprises a feedback loop having a feedback loop parameter and that selectively adjusts said feedback loop parameter based on said at least one of said calibration parameters,wherein said phase locked loop module comprises a fractional phase locked loop module and said feedback loop parameter includes a ratio of a scaling factor, andwherein said fractional phase locked loop module comprises;

    a phase frequency detector module that communicates with said FBAR circuit and that receives said reference frequency; and

    a charge pump module that communicates with said phase frequency detector module;

    a voltage controlled oscillator that communicates with said charge pump module and that generates an output frequency; and

    a scaling module that communicates with said voltage controlled oscillator and said phase frequency detector module, that selectively divides said output frequency by first and second scaling factors and that selectively adjusts a ratio of said first and second scaling factors based on said at least one of said calibration parameters.

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