SNLA370A December   2020  – December 2020 DP83TG720R-Q1 , DP83TG720S-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Device Comparison
    1. 2.1 Feature Comparison
    2. 2.2 Pin Map Comparison
    3. 2.3 Strap Comparison
      1. 2.3.1 PHY Address Straps
      2. 2.3.2 MAC Interface, Master/Slave, Autonomous Strap
    4. 2.4 Power-Supply Comparison
    5. 2.5 MDI Comparison
  4. 3Reference Schematics
  5. 4Summary
  6. 5Revision History

2.3.2 MAC Interface, Master/Slave, Autonomous Strap

Strap features on RX_D0, RX_D1, RX_D2, LED_0, and LED_1 are same for all four devices. They can be used by keeping the strap resistors open or by using a pull up resistor. Test Mode straps are not not supported on DP83TG720. This allows those strap pins to be used as two level straps. The two PHYs can be configured in Test Modes via register access.

When strap resistors are not used, the PHY's internal pull down resistors will configure the PHY in Mode 1 by default. However, for LED pins it is recommended to use pull down resistor in parallel with the an LED when using Mode 1.

Table 2-6 MAC Interface, Master/Slave, Autonomous Strap Comparison TableAUTOAUTO
PIN NO. PIN NAME DP83TC811 DP83TG720
STRAP MODE Table 2-7 STRAP STRAP MODE Table 2-8 STRAP
26 RX_D0 MAC[0] TEST[0] MAC[0] NA
Mode 1 0 0 Mode 1 0
Mode 2 0 1 NA NA
Mode 3 1 0 NA NA
Mode 4 1 1 Mode 2 1
25 RX_D1 MAC[1] TEST[1] MAC[1] NA
Mode 1 0 0 Mode 1 0
Mode 2 0 1 NA NA
Mode 3 1 0 NA NA
Mode 4 1 1 Mode 2 1
24 RX_D2 MAC[1] TEST[2] MAC[2] NA
Mode 1 0 0 Mode 1 0
Mode 2 0 1 NA NA
Mode 3 1 0 NA NA
Mode 4 1 1 Mode 2 1
35 LED_0 MS RESERVED MS NA
Mode 1 0 Mode 1 0
Mode 2 RESERVED RESERVED NA NA
Mode 3 RESERVED RESERVED NA NA
Mode 4 1 Mode 2 1
6 LED_1 RESERVED RESERVED
Mode 1 0 Mode 1 0
Mode 2 RESERVED RESERVED NA NA
Mode 3 RESERVED RESERVED NA NA
Mode 4 1 Mode 2 1

Required strap resistor values for MAC, Master/Slave and Autonomous mode configurations are in Table 2-7 for DP83TC811 and in Table 2-8 for DP83TG720.

Table 2-7 Recommended Resistor Ratios For DP83TC811's MAC, Master/Slave and Autonomous mode configurations: 4-level straps
MODE IDEAL RH (kΩ) IDEAL RL (kΩ)
1 OPEN OPEN
2 10 2.49
3 5.76 2.49
4 2.49 OPEN
Table 2-8 Recommended Resistor Ratios For DP83TG720's MAC, Master/Slave and Autonomous mode configurations: 2-level straps
MODE IDEAL RH (kΩ)
1 OPEN
2 2.49