SNLA293 May   2022 DP83TC811R-Q1 , DP83TC811S-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Hardware Configuration
    1. 2.1 Schematic
  4. 3Software Configuration
  5. 4Testing PMA
    1. 4.1 PMA Testing Procedure
  6. 5Testing IOP: Link-up and Link-down
    1. 5.1 IOP Testing Procedure
  7. 6Testing SQI
    1. 6.1 SQI Testing Procedure
    2. 6.2 SQI Mapping with Link Quality
  8. 7Testing TDR
    1. 7.1 TDR Testing Procedure
  9. 8Testing EMC/EMI
  10. 9Revision History

2.1 Schematic

Schematics and the right components for MDI, reference clock, and power network are very critical for the performance of 100Base-T1 PHY. This section captures the recommended schematics and component values used during OA TC1 testing.

Figure 2-1 Power Supply Network
Table 2-1 Power Supply Parameters, Components and Values
Parameter/Component Value
VDDIO 1.8 V, 2.5 V, or 3.3 V
De-Coupling Capacitors VDDIO 10 nF, 100 nF, 1uF, 10uF
(Optional) Ferrite Bead VDDIO 1 kΩ at 100 MHz (BLM18AG102SH)
VDDA 3.3 V
De-Coupling Capacitors VDDA 10 nF, 100 nF, 1uF, 10uF
(Optional) Ferrite Bead VDDA 1 kΩ at 100 MHz (BLM18AG102SH)
Figure 2-2 MDI and Crystal Schematic
Table 2-2 Crystal and MDI Parameters, Components and Values
Parameter/ComponentValue
Filter - R1, R2 (1% accurate) 22 Ω
Filter - C1, C2 (2% accurate) 22pF
Filter - C3, C4 (2% accurate) 47pF
Filter - L1, L2 (2% accurate) 120nH
DC Blocking Capacitors (1% accurate, 100V)0.1 μF
Common-Mode ChokeTDK: ACT1210L-201
TDK: ACT45L-201
Murata: DLW32MH201XK2
Murata: DLW43MH201XK2L
Pulse: AE2002
Common Mode Termination Resistors (1% accurate,0.75 W, Size: 2010)1 kΩ
MDI Coupling Capacitor4.7 nF
ESD Shunt (5% accurate, 0.125 W, Size: 0805)100 kΩ
Isolation Resistor 1 (0.25 W, Size: 1206)0 Ω
Isolation Resistor 2 (0.25 W, Size: 1206)0 Ω
Isolation CapacitorNot populated
Crystal
R_XI100 Ω
R_XO

200 Ω

Adding series resistor is seen to make crystal oscillator more immune to board parasitics, noise and helps in quick startup.

TI recommends to use a resistor of value 200 ohms. As this resistor controls the crystal wattage, its value should be chosen in consultation with the crystal vendor.