DP83822I: Magnetic supply requirement at No traffic

Takeshi Sasaki

Part Number: DP83822I

Hi Team,

In the datasheet page 95 Table 137, magnetic supply requires 22mA at 100BASE-TX, even at No traffic condition. Could you tell me why magnetic supply requires 22mA even at No traffic condition? In order the customer to calculate the power tree design, could you advise above topic? Thank you for your support.

Best regards,

Takeshi Sasaki

over 7 years ago

0 Takeshi Sasaki over 7 years ago

TI__Expert 4480 points

Could you give me any feedback?

0 Geet Modi over 7 years ago in reply to Takeshi Sasaki

TI__Mastermind 26320 points

As per standard, continuous signalling is present on the line irrespective of the actual data. To drive the signalling, Tx driver derives the current from center tap.

Regards,
Geet

0 Takeshi Sasaki over 7 years ago in reply to Geet Modi

TI__Expert 4480 points

Hi Modi,

Thank you for your comments. Let me confirm one thing. Before the link up, there is no magnetic current, and after link up, there is magnetic current because it requires signaling as per standard. Is it correct understanding?

0 Geet Modi over 7 years ago in reply to Takeshi Sasaki

TI__Mastermind 26320 points

Transmitter continues to transmit the Link Pulse (NLP), hence it will drive current. You can always put the Phy in low power state to avoid the leakage.

Regards,
Geet

0 Takeshi Sasaki over 7 years ago in reply to Geet Modi

TI__Expert 4480 points

Hi Modi,

Thank you for your comments.

0 Takeshi Sasaki over 7 years ago in reply to Geet Modi

TI__Expert 4480 points

Hi Geet,

Thank you for your comments.

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DP83822I: Magnetic supply requirement at No traffic