SNLA423 March   2023 DP83826E

 

  1. 1Trademarks
  2. 2DP83826 Application Overview
  3. 3Troubleshooting the Application
    1. 3.1 Read and Check Register Values
    2. 3.2 Schematic and Layout Checklist
    3. 3.3 Component Checklist
    4. 3.4 Peripheral Pin Checks
      1. 3.4.1 Power Supplies
      2. 3.4.2 Probe the XI Clock
      3. 3.4.3 Probe the RESET_N Signal
      4. 3.4.4 Probe the Strap Pins During Initialization
      5. 3.4.5 Probe the Serial Management Interface Signals (MDC, MDIO)
      6. 3.4.6 Probe the MDI Signals
    5. 3.5 Link Quality Check
    6. 3.6 Built-In Self Test with Various Loopback Modes
    7. 3.7 Debugging MAC Interface
    8. 3.8 Tools and References
      1. 3.8.1 DP83826 Register Access
      2. 3.8.2 Extended Register Access
      3. 3.8.3 Application Note References
  4. 4Conclusion
  5. 5Revision History

3.3 Component Checklist

Magnetics:

The following guidelines are the main specifications to reference for compatible magnetics:

Table 3-2 Recommended Transformers
MANUFACTURER PART NUMBER
Pulse Electronics HX1198FNL
HX1188NL
HX1188FNL
Table 3-3 Magnetic Isolation Requirements
PARAMETER TEST CONDITIONS TYP UNIT
Turns Ratio ±2% Tolerance 1:1 -
Insertion Loss 1-100 MHz -1 dB
Return Loss 1-30 MHz -16 dB
30-60 MHz -12 dB
60-80 MHz -10 dB
Differential to Common Mode Rejection Ratio 1-50 MHz -30 dB
50-150 MHz -20 dB
Crosstalk 30 MHz -35 dB
60 MHz -30 dB
Isolation HPOT 1500 Vrms

If these exact requirements cannot be met, the following allowances can be made:

  • Turns ratio
    • Ideally 2%, but 3% is tolerable.
  • Inductance
    • High inductance is preferred. Usual numbers seen are around 350 μH.
  • Insertion loss
    • As close to 0 dB as possible compared to specified value for each range stated in data sheet. If specification gives -1 dB as typical. finding a component with -1 dB, -0.9 dB, … is recommended.
  • Return loss
    • At or lower than the magnitude specified in data sheet. If specification gives -16 dB as typical, finding a component with -16 dB, -17 dB, … is recommended.

Crystal

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

Table 3-4 25-MHz Crystal Specifications
PARAMETERTEST CONDITIONMINTYPMAXUNIT
Frequency25MHz
Frequency ToleranceOperational Temperature-100100ppm
Load Capacitance1540pF
ESR 50 Ω

Table 3-5 25-MHz Oscillator Specifications
PARAMETER TEST CONDITION MIN TYP MAX UNIT
Frequency 25 MHz
Frequency Tolerance Operational Temperature ±50 ppm
Frequency Stability 1 year aging ±50 ppm
Rise / Fall Time 20% - 80% 5 ns
Symmetry Duty Cycle 40% 60%
Jitter RMS Integration Band: 12 kHz to 5 MHz 11 ps