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

2.3.1 PHY Address Straps

Table 2-3 shows the PHY address strap comparison between DP83TC811 and DP83TG720.

DP83TC811 can support 16 PHY addresses from 0x00 to 0x0F. DP83TG720 can support 9 PHY addresses: 0x00, 0x04, 0x05, 0x08, 0x0A, 0x0C, 0x0D, 0x0D, 0x0E, 0x0F. By provisioning for a pull up and pull down resistor on pin 14 and 15 of the PHY, both devices can be supported by simply changing the resistor combination.

Table 2-3 PHY Address Strap Comparison Table
Pin No. Pin Name DP83TC811 DP83TG720
STRAP MODE Table 2-4 STRAP STRAP MODE Table 2-5 STRAP
15 RX_DV/RX_CTRL
RX_CTRL (DP83TG720)		 PHYADD[0] PHYADD[2] PHYADD[0] PHYADD[2]
Mode 1 0 0 Mode 1 0 0
Mode 2 0 1 Mode 2 0 1
Mode 3 1 0 NA NA NA
Mode 4 1 1 Mode 3 1 1
14 RXER
STRP1 (DP83TG720)		 PHYADD[1] PHYADD[3] PHYADD[1] PHYADD[3]
Mode 1 0 0 Mode 1 0 0
Mode 2 0 1 Mode 2 0 1
Mode 3 1 0 NA NA NA
Mode 4 1 1 Mode 3 1 1

Table 2-4 shows strap resistor values for DP83TC811's phy address and Table 2-5 show the recommended strap resistor values for DP83TG720's phy address. RH are pull-up resistors and RL are pull down resistors.

Table 2-4 Recommended 4-level Strap Resistor Ratios For DP83TC811
MODE IDEAL RH (kΩ)1
for VDDIO = 3.3 V/2.5V/1.8V		 IDEAL RL (kΩ)1
for VDDIO = 3.3 V/2.5V/1.8V
1 OPEN OPEN
2 10 2.49
3 5.76 2.49
4 2.49 OPEN
  1. 1% resistor accuracy
Table 2-5 Recommended 3-level Strap Resistor Ratios for DP83TG720
MODE IDEAL RH (kΩ) 1
for VDDIO = 3.3 V		 IDEAL RH (kΩ) 2
for VDDIO = 2.5 V 		IDEAL RH (kΩ)1
for VDDIO = 1.8V
1 OPEN OPEN OPEN
2 13 12 4
3 4.5 2 0.8
  1. 10% resistor accuracy
  2. 1% resistor accuracy