DP83822IF: Series termination on signal lines

Remya Reghuvaran

Part Number: DP83822IF

Hi,

As per the datasheet of DP83822IF, by setting [4:1] bit of 0x0461 IO MUX GPIO Control Register (IOCTRL) we can set the series termination for the signal lines. So do we need to provide additional series termination resistor in hardware?

In a reference design we observed that 100E series termination resistors are used in the PCB. Is it really required. There are some space limitations in my PCB. That's why I asked this question. Could you please advise?

Regards,

Remya R

over 3 years ago

0 Gokul Koraganji over 3 years ago

TI__Mastermind 19250 points

Hi Remya,

We don't need external series termination on RX_D0,1,2,3. The IOCTRL Register can be used to program the internal series impedance of these pins to match the board trace impedance.

--
Regards,
Gokul.

0 Remya Reghuvaran over 3 years ago in reply to Gokul Koraganji

Prodigy 40 points

Hi Gokul,

So do we need to require external series termination on TX_EN, TX_CLK, TX_D0-TX_D3,RX_DV, RX_ER and RX_CLK? Please confirm.

Also in my design, using MII mode I connected TX_EN/TX_CTRL(Pin#3) of DP83822 with TX_EN pin of MAC. Is it required to connect this pin with TX_ER pin of MAC for MII? Currently I'm left the TX_ER pin of MAC as NC. Please share your suggestions on this also.

Regards,

Remya R

0 Gokul Koraganji over 3 years ago in reply to Remya Reghuvaran

TI__Mastermind 19250 points

Hi Remya,

TX_ER is an optional feature and can be left out of the application.

Regarding the series termination on TX_* pins, it depends on the series impedance of the MAC/Host. I suggest checked this with the MAC/Host team.

--
Regards,
Gokul.

Interface

Interface forum

DP83822IF: Series termination on signal lines