參數(shù)資料
      型號: ADF4251
      廠商: Analog Devices, Inc.
      英文描述: Dual Fractional-N/Integer-N Frequency Synthesizer
      中文描述: 雙Fractional-N/Integer-N頻率合成器
      文件頁數(shù): 1/28頁
      文件大?。?/td> 387K
      代理商: ADF4251
      REV. 0
      Information furnished by Analog Devices is believed to be accurate and
      reliable. However, no responsibility is assumed by Analog Devices for its
      use, nor for any infringements of patents or other rights of third parties that
      may result from its use. No license is granted by implication or otherwise
      under any patent or patent rights of Analog Devices. Trademarks and
      registered trademarks are the property of their respective owners.
      ADF4251
      Dual Fractional-N/Integer-N
      Frequency Synthesizer
      One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
      Tel: 781/329-4700
      Fax: 781/326-8703
      2003 Analog Devices, Inc. All rights reserved.
      www.analog.com
      FEATURES
      3.0 GHz Fractional-N/1.2 GHz Integer-N
      2.7 V to 3.3 V Power Supply
      Separate V
      P
      Allows Extended Tuning Voltage to 5 V
      Programmable Dual Modulus Prescaler
      RF: 4/5, 8/9
      IF: 8/9, 16/17, 32/33, 64/65
      Programmable Charge Pump Currents
      3-Wire Serial Interface
      Digital Lock Detect
      Power-Down Mode
      Programmable Modulus on Fractional-N Synthesizer
      Trade-Off Noise versus Spurious Performance
      Software and Hardware Power-Down
      APPLICATIONS
      Base Stations for Mobile Radio (GSM, PCS, DCS,
      CDMA, WCDMA)
      Wireless Handsets (GSM, PCS, DCS, CDMA, WCDMA,
      PHS)
      Wireless LANs
      Communications Test Equipment
      CATV Equipment
      FUNCTIONAL BLOCK DIAGRAM
      ADF4251
      2
      DOUBLER
      OUTPUT
      MUX
      4-BIT R
      COUNTER
      PHASE
      FREQUENCY
      DETECTOR
      LOCK
      DETECT
      CHARGE
      PUMP
      REFERENCE
      REF
      IN
      V
      DD
      1
      V
      DD
      2
      V
      DD
      3
      DV
      DD
      V
      P
      1
      V
      P
      2
      R
      SET
      24-BIT
      DATA
      REGISTER
      CLK
      DATA
      LE
      RF
      IN
      A
      RF
      IN
      B
      CP
      RF
      CP
      IF
      2
      DOUBLER
      15-BIT R
      COUNTER
      CHARGE
      PUMP
      PHASE
      FREQUENCY
      DETECTOR
      MUXOUT
      A
      GND
      1
      A
      GND
      2
      D
      GND
      CP
      GND
      1 CP
      GND
      2
      IF
      IN
      B
      IF
      IN
      A
      FRACTIONAL N
      RF DIVIDER
      INTEGER N
      IF DIVIDER
      CE
      FROM
      REFIN
      GENERAL DESCRIPTION
      The ADF4251 is a dual fractional-N/integer-N frequency
      synthesizer that can be used to implement local oscillators
      (LO) in the upconversion and downconversion sections of
      wireless receivers and transmitters. Both the RF and IF syn-
      thesizers consist of a low noise digital PFD (phase frequency
      detector), a precision charge pump, and a programmable refer-
      ence divider. The RF synthesizer has a - based fractional
      interpolator that allows programmable fractional-N division.
      The IF synthesizer has programmable integer-N counters. A
      complete PLL (phase-locked loop) can be implemented if the
      synthesizer is used with an external loop filter and VCO (volt-
      age controlled oscillator).
      Control of all the on-chip registers is via a simple 3-wire inter-
      face. The devices operate with a power supply ranging from
      2.7 V to 3.3 V and can be powered down when not in use.
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