SNAU182A March   2021  – May 2022

 

  1.   Trademarks
  2. 1LMX2571EPEVM Evaluation Module
    1. 1.1 Evaluation Module Contents
    2. 1.2 Evaluation Setup Requirement
    3. 1.3 Resources
  3. 2Setup
    1. 2.1 Connection Diagram
    2. 2.2 Power Supply
    3. 2.3 Reference Clock
    4. 2.4 RF Output
    5. 2.5 Programming
    6. 2.6 Evaluation Software
    7. 2.7 EVM Strap Options
      1. 2.7.1 J11 Header
      2. 2.7.2 J12 Header
  4. 3Typical Measurement
    1. 3.1 Default Configuration
      1. 3.1.1 Loop Filter
      2. 3.1.2 Typical Output
    2. 3.2 Additional Tests
      1. 3.2.1 FSK Modulation
      2. 3.2.2 Register Readback
  5. 4Schematic
  6. 5Board Construction
    1. 5.1 PCB Layer Stack-Up
    2. 5.2 PCB Layout
  7. 6Bill of Materials
  8. 7Troubleshooting Guide
  9.   A Using Different Reference Clock
  10.   B Reference PRO
    1.     B.1 Output Frequency Selection
    2.     B.2 Output Format Selection
    3.     B.3 Typical Output Characteristics
    4.     B.4 Firmware Update
  11.   C Revision History

3.1.1 Loop Filter

Table 3-1 lists the parameters for the loop filter.

Table 3-1 Loop Filter Configuration
PARAMETER VALUE
VCO frequency Designed for 4.8 GHz, but works over the whole frequency range
VCO gain 56 MHz/V
Effective charge pump gain 2500 µA
Phase detector frequency 80 MHz
Loop bandwidth 205 kHz
Phase margin 40 degrees
C1_LF 390 pF
C2_LF 4.7 nF
R2_LF 680 Ω
R3_LF = R4_LF (Internal) 800 Ω
C3_LF (Internal) 50 pF
C4_LF (Internal) 100 pF
GUID-097B1D6E-EE55-4516-8929-22C305E295A7-low.pngFigure 3-1 Loop Filter