ZHCSP40B October   2021  – June 2022 LMX2571-EP

PRODUCTION DATA  

  1. 特性
  2. 应用
  3. 说明
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Differences Between the LMX2571 and LMX2571-EP
      2. 7.3.2  Reference Oscillator Input
      3. 7.3.3  R-Dividers and Multiplier
      4. 7.3.4  PLL Phase Detector and Charge Pump
        1. 7.3.4.1 CPout Pin Charge Pump Current
        2. 7.3.4.2 Charge Pump Current When Using External VCO
      5. 7.3.5  PLL N-Divider and Fractional Circuitry
      6. 7.3.6  Partially Integrated Loop Filter
      7. 7.3.7  Low-Noise, Fully Integrated VCO
      8. 7.3.8  External VCO Support
      9. 7.3.9  Programmable RF Output Divider
      10. 7.3.10 Programmable RF Output Buffer
      11. 7.3.11 Integrated TX, RX Switch
      12. 7.3.12 Power Down
      13. 7.3.13 Lock Detect
      14. 7.3.14 FSK Modulation
      15. 7.3.15 FastLock
      16. 7.3.16 Register Readback
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation Mode
      2. 7.4.2 Duplex Mode
      3. 7.4.3 FSK Mode
    5. 7.5 Programming
      1. 7.5.1 Recommended Initial Power on Programming Sequence
      2. 7.5.2 Recommended Sequence for Changing Frequencies
    6. 7.6 Register Maps
      1. 7.6.1  R60 Register (offset = 3Ch) [reset = 4000h]
      2. 7.6.2  R58 Register (offset = 3Ah) [reset = C00h]
      3. 7.6.3  R53 Register (offset = 35h) [reset = 2802h]
      4. 7.6.4  R47 Register (offset = 2Fh) [reset = 0h]
      5. 7.6.5  R46 Register (offset = 2Eh) [reset = 1Ah]
      6. 7.6.6  R42 Register (offset = 2Ah) [reset = 210h]
      7. 7.6.7  R41 Register (offset = 29h) [reset = 810h]
      8. 7.6.8  R40 Register (offset = 28h) [reset = 101Ch]
      9. 7.6.9  R39 Register (offset = 27h) [reset = 11F0h]
      10. 7.6.10 R35 Register (offset = 23h) [reset = 647h]
      11. 7.6.11 R34 Register (offset = 22h) [reset = 1000h]
      12. 7.6.12 R33 Register (offset = 21h) [reset = 0h]
      13. 7.6.13 R25 to R32 Register (offset = 19h to 20h) [reset = 0h]
      14. 7.6.14 R24 Register (offset = 18h) [reset = 10h]
      15. 7.6.15 R23 Register (offset = 17h) [reset = 10A4h]
      16. 7.6.16 R22 Register (offset = 16h) [reset = 8584h]
      17. 7.6.17 R21 Register (offset = 15h) [reset = 101h]
      18. 7.6.18 R20 Register (offset = 14h) [reset = 28h]
      19. 7.6.19 R19 Register (offset = 13h) [reset = 0h]
      20. 7.6.20 R18 Register (offset = 12h) [reset = 0h]
      21. 7.6.21 R17 Register (offset = 11h) [reset = 0h]
      22. 7.6.22 R9 to R16 Register (offset = 9h to 10h) [reset = 0h]
      23. 7.6.23 R8 Register (offset = 8h) [reset = 10h]
      24. 7.6.24 R7 Register (offset = 7h) [reset = 10A4h]
      25. 7.6.25 R6 Register (offset = 6h) [reset = 8584h]
      26. 7.6.26 R5 Register (offset = 5h) [reset = 101h]
      27. 7.6.27 R4 Register (offset = 4h) [reset = 28h]
      28. 7.6.28 R3 Register (offset = 3h) [reset = 0h]
      29. 7.6.29 R2 Register (offset = 2h) [reset = 0h]
      30. 7.6.30 R1 Register (offset = 1h) [reset = 0h]
      31. 7.6.31 R0 Register (offset = 0h) [reset = 3h]
  8. Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Direct Digital FSK Modulation
      2. 8.1.2  Frequency and Output Port Switching
      3. 8.1.3  OSCin Configuration
      4. 8.1.4  Register R0 F1F2_INIT, F1F2_MODE Usage
      5. 8.1.5  FastLock With External VCO
      6. 8.1.6  OSCin Slew Rate
      7. 8.1.7  RF Output Buffer Power Control
      8. 8.1.8  RF Output Buffer Type
      9. 8.1.9  MULT Multiplier
      10. 8.1.10 Integrated VCO
    2. 8.2 Typical Applications
      1. 8.2.1 Synthesizer Duplex Mode
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Synthesizer Duplex Mode Application Curves
      2. 8.2.2 PLL Duplex Mode
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 PLL Duplex Mode Application Curves
      3. 8.2.3 Synthesizer/PLL Duplex Mode
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Synthesizer/PLL Duplex Mode Application Curves
    3. 8.3 Do's and Don'ts
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 接收文档更新通知
    4. 11.4 支持资源
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 术语表
  12. 12Mechanical, Packaging, and Orderable Information

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RF Output Buffer Type

Registers R35, OUTBUF_TX_TYPE, OUTBUF_RX_TYPE are used to configure the RF output buffer type between open drain and push-pull. Push-pull is easy to use; all that is required is a DC-blocking capacitor at the output. The output waveform is square wave and therefore, harmonics rich. Open-drain output provides an option to reduce the harmonics using an LC resonant pullup network at its output. Table 8-5 summarizes an example an open-drain vs. push-pull application.

Table 8-5 RF Output Buffer Type
BUFFER TYPEOPEN-DRAINPUSH-PULL
Connection DiagramGUID-7C8AD47C-4C2A-4882-A067-50F976168BBA-low.gifGUID-296087E5-5180-481E-A073-58A42B187436-low.gif
Output Power470 MHz480 MHz490 MHz470 MHz480 MHz490 MHz
fo2.7 dBm2.8 dBm2.8 dBm–0.1 dBm0 dBm0.1 dBm
2fo–31 dBc–30.7 dBc–30.5 dBc–30.4 dBc–30.2 dBc–30 dBc
3fo–17.3 dBc–17.9 dBc–18.1 dBc–11.9 dBc–12.1 dBc–12.4 dBc
4fo–39 dBc–40.4 dBc–41.6 dBc–28.5 dBc–28.4 dBc–28.1 dBc
5fo–18.1 dBc–17.8 dBc–17.6 dBc–15.6 dBc–15.6 dBc–15.7 dBc
6fo–27.6 dBc–27.2 dBc–28.5 dBc–29.5 dBc–29.8 dBc–29.3 dBc

Clearly, with a proper LC pull up in open-drain architecture, the 3rd to 5th harmonics could be reduced.