SNAU278 July   2022

 

  1.   Abstract
  2.   Trademarks
  3. 1LMX2594PSEVM Evaluation Module
    1. 1.1 Evaluation Module Contents
    2. 1.2 Evaluation Setup Requirement
    3. 1.3 Resources
  4. 2Setup
    1. 2.1 Connection Diagram
    2. 2.2 Power Supply
    3. 2.3 Reference Clock
    4. 2.4 SYNC Input
    5. 2.5 RF Output
    6. 2.6 Programming
    7. 2.7 Evaluation Software
  5. 3Typical Measurement
    1. 3.1 Category 3 Synchronization
    2. 3.2 Phase Noise Improvement
  6. 4Schematic
  7. 5PCB Layout and Layer Stack-up
    1. 5.1 PCB Layer Stack-Up
    2. 5.2 PCB Layout
  8. 6Bill of Materials
  9. 7EVM Modification
  10. 8Troubleshooting Guide
  11. 9Reference PRO
    1. 9.1 Output Frequency Selection
    2. 9.2 Output Format Selection
    3. 9.3 Typical Output Characteristics
    4. 9.4 Firmware Update

3.1 Category 3 Synchronization

Use the flow chart in the data sheet to determine the phase synchronization category. If it is a category 3 synchronization, there is limitation to the reference clock frequency and the timing of the SYNC signal with respect to the reference clock is critical. Shown below is a category 3 synchronization example.

GUID-20220721-SS0I-J4JL-05H0-QK2DBL95SD5K-low.pngFigure 3-1 Category 3 TICS Pro Configuration

If it is a category 3 synchronization, VCO_PHASE_SYNC should be checked to put the devices in SYNC mode. After programming, the outputs from the two LMX2594 devices may not be phase-aligned.

GUID-20220720-SS0I-VKNB-N8XK-BTM6FGLHWWKW-low.pngFigure 3-2 Output Phases Before Synchronization

A timing critical SYNC pulse is needed to trigger synchronization.

GUID-20220720-SS0I-FGH4-RX6S-JRPRZCQZGDN3-low.pngFigure 3-3 Timing Critical SYNC Pulse
GUID-20220720-SS0I-GB7X-FDRH-FCM0XQM86FBD-low.pngFigure 3-4 Output Phases After Synchronization