DP83848Q-Q1: Usage to pull down TX_CLK and RX_CLK

Tomoaki Yoshida91

Part Number: DP83848Q-Q1

Hi team,

Our customer will pull down TX_CLK and RX_CLK.

When the ECU does not communicate, the PHY is turned off the power, so it is neccesary to fix it so as not to become indeterminate.

I think that it is no problem to pull down TX_CLK and RX_CLK.

Please let me know if you have any concerns.

Best regards,

Tomoaki Yoshida

over 8 years ago

0 Aniruddha Khadye over 8 years ago

TI__Mastermind 18425 points

Hello,

Is the system in RMII mode where the RX_CLK and TX_CLK is not used? It is ok to pull down those pins when they are unused.

-Regards,
Aniruddha

0 Tomoaki Yoshida91 over 8 years ago in reply to Aniruddha Khadye

Genius 5255 points

Hi Aniruddha-san,

Thank you for your support.

It is MII system, not RMII.

Since it is normally operated, does not the pull-down resistor affect at that time?

Please tell me if there is a recommended resistance value.

Best regards,

Tomoaki Yoshida

0 Geet Modi over 8 years ago in reply to Tomoaki Yoshida91

TI__Mastermind 26320 points

Hi Tomoaki-san,

If MAC interface chosen is MII, then phy drives these lines (TX_CLK and RX_CLK) to provide clock in ACTIVE state. Both the signals are output from Phy, weak pull-down can be added to keep the IO state determinate while power off. You can use weak-pull downs of ~10K.

Regards,
Geet

0 Tomoaki Yoshida91 over 8 years ago in reply to Geet Modi

Genius 5255 points

Hi Geet-san,

Thank you for your support.

I will refer to your advice.

Best regards,

Tomoaki Yoshida

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DP83848Q-Q1: Usage to pull down TX_CLK and RX_CLK