SNLA239D May   2021  – April 2025 DP83867CR , DP83867CS , DP83867E , DP83867IR , DP83867IS , DP83869HM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Standards and System Requirements
    1. 1.1 Standards
    2. 1.2 Test Equipment Suppliers
    3. 1.3 Test System Requirements
    4. 1.4 Software Setup and Installation
  5. 2Ethernet Physical Layer Compliance Testing
    1. 2.1 Standard Test Setup and Procedures
    2. 2.2 1000BASE-T
      1. 2.2.1 Test Mode 1
        1. 2.2.1.1 Template
        2. 2.2.1.2 Peak Voltage
        3. 2.2.1.3 Droop
      2. 2.2.2 Test Mode 2
        1. 2.2.2.1 Jitter Master Unfiltered
      3. 2.2.3 Test Mode 4
        1. 2.2.3.1 Distortion
        2. 2.2.3.2 Common-Mode Voltage
        3. 2.2.3.3 Return Loss
        4. 2.2.3.4 Common-Mode Noise Rejection
    3. 2.3 100BASE-TX
      1. 2.3.1  Template (Active Output Interface)
      2. 2.3.2  Differential Output Voltage
      3. 2.3.3  Signal Amplitude Symmetry
      4. 2.3.4  Rise and Fall Time
      5. 2.3.5  Waveform Overshoot
      6. 2.3.6  Jitter
      7. 2.3.7  Duty Cycle Distortion
      8. 2.3.8  Return Loss
      9. 2.3.9  Common-Mode Voltage
      10. 2.3.10 Common-Mode Noise Rejection
    4. 2.4 10BASE-Te
      1. 2.4.1 Link Pulse
      2. 2.4.2 10Base-Te Standard
        1. 2.4.2.1 TP_IDL
        2. 2.4.2.2 MAU, Internal
        3. 2.4.2.3 Jitter With TPM
        4. 2.4.2.4 Jitter Without TPM
        5. 2.4.2.5 Differential Voltage
        6. 2.4.2.6 Common-Mode Voltage
        7. 2.4.2.7 Return Loss
        8. 2.4.2.8 Harmonic Content
        9. 2.4.2.9 Common-Mode Rejection
  6. 3Debug Test Methods
  7. 4References
  8. 5Revision History
  9.   A Appendix A: Outline of Ethernet Compliance Tests for DP8386x
  10.   B Appendix B: Ethernet Compliance Testing MDIO Register Writes for DP8386x

2.4.2.7 Return Loss

Purpose: To make sure that the return loss is above the specified attenuation.

Pass Condition: The reflection of any incident signal to the PHY must be attenuated:

≥ 15 dB over the frequency range of 5.0 MHz to 10 MHz

Specific Test Setup: Two waveform inputs might be necessary depending on testing setup. Verify the correct test fixture connections. Configure the PHY to be in reverse loopback mode by setting MDIO registers according to 10 Base Standard in Appendix B. Note a spectrum analyzer might be needed depending on Ethernet Compliance Software.