SNLA437A December   2023  – October 2025 DP83822H , DP83822HF , DP83822I , DP83822IF , DP83826I

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1DP83822 Application Overview
  5. 2Troubleshooting the PHY Application
    1. 2.1 Schematic and Layout Checklist
    2. 2.2 Device Health Checks
      1. 2.2.1 Power Supply Ramp Sequence Check
        1. 2.2.1.1 Power Supply Ramp with Unstable XI Clock
      2. 2.2.2 Voltage Checks
      3. 2.2.3 Probe the RESET_N Signal
      4. 2.2.4 Probe the RBIAS pin
      5. 2.2.5 Probe the XI Clock
      6. 2.2.6 Probe the Strap Pins During Initialization
      7. 2.2.7 Probe the Serial Management Interface (MDC, MDIO) Signals
        1. 2.2.7.1 Read and Check Register Values
          1. 2.2.7.1.1 Extended Register Access
    3. 2.3 MDI Health Checks
      1. 2.3.1 Magnetics
      2. 2.3.2 Probe the MDI Signals
      3. 2.3.3 Link Quality Check
      4. 2.3.4 Debug the Fiber Connection
      5. 2.3.5 Debug the Start of Frame Detect
      6. 2.3.6 Compliance
    4. 2.4 MII Health Checks
      1. 2.4.1 MII Check
      2. 2.4.2 RMII Check
      3. 2.4.3 RGMII Check
    5. 2.5 Loopback and PRBS
      1. 2.5.1 Loopback Modes
      2. 2.5.2 Transmitting and Receiving Packets With the MAC
      3. 2.5.3 Transmitting and Receiving Packets With BIST
  6. 3Tools and References
    1. 3.1 DP83822 Register Access
    2. 3.2 Software and Driver Debug on Linux
      1. 3.2.1 Common Terminal Outputs and Solutions
  7. 4Summary
  8. 5References
  9. 6Revision History

Probe the XI Clock

The following guidelines are the main specifications to reference for compatible crystals.

Table 2-4 25-MHz Crystal Specification
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
Frequency25MHz
Frequency ToleranceIncluding operational temperature, aging and other factors-100

100

ppm
Load Capacitance1040pF

Table 2-5 25-MHz Oscillator Specification
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
Frequency25MHz
Frequency ToleranceIncluding operational temperature, aging and other factors-100

100

ppm
Rise / Fall Time10% - 90%8nsec
Jitter (Short Term)Cycle-to-cycle50100psec
Jitter (Long Term)Accumulative over 10 ms1nsec
SymmetryDuty Cycle4060%
Load Capacitance1530pF
Table 2-6 50-MHz Oscillator Specification
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
Frequency50MHz
Frequency ToleranceIncluding operational temperature, aging and other factors-100

100

ppm
Rise / Fall Time10% - 90%8nsec
Jitter (Short Term)Cycle-to-cycle50psec
Jitter (Long Term)Accumulative over 10 ms1nsec
SymmetryDuty Cycle4060%
Load Capacitance1530pF

Verify the frequency and signal integrity. For link integrity the reference clock is recommended to be:

  • MII/RGMII and RMII Leader Modes

    • 25MHz ±100ppm

  • RMII Follower Mode

    • 50MHz ±100ppm