SNAU246A June   2020  – January 2021 LMX2820

 

  1. 1Trademarks
  2. 2LMX2820EVM Evaluation Module
    1. 2.1 Evaluation Module Contents
    2. 2.2 Evaluation Setup Requirement
    3. 2.3 Resources
  3. 3Setup
    1. 3.1 Connection Diagram
    2. 3.2 Power Supply
    3. 3.3 Reference Clock
    4. 3.4 RF Output
    5. 3.5 Programming
    6. 3.6 Evaluation Software
  4. 4Typical Measurement
    1. 4.1 Default Configuration
      1. 4.1.1 Loop Filter
      2. 4.1.2 Typical Output
    2. 4.2 Additional Tests
      1. 4.2.1 SYSREF Example
      2. 4.2.2 Offset Mixing With PFDIN Pin
      3. 4.2.3 External VCO Mode
      4. 4.2.4 Register Readback
  5. 5Schematic
  6. 6PCB Layout and Layer Stack-Up
    1. 6.1 PCB Layer Stack-Up
    2. 6.2 PCB Layout
  7. 7Bill of Materials
  8. 8Troubleshooting Guide
    1.     A Using Different Reference Clock
      1.      B USB2ANY Firmware Upgrade
        1.       C Revision History

4.1.1 Loop Filter

The parameters for the loop filter are listed in Table 4-1.

Table 4-1 Loop Filter Configuration
PARAMETERVALUE
C1_LF470 pF
C2_LF68 nF
C3_LF2.2 nF
R2_LF68.1 Ω
R3_LF18.2 Ω
GUID-498ECF52-3161-4F49-941B-CE7269E57E16-low.pngFigure 4-1 Loop Filter