TLK105: RD± input voltage when TLK105 power is turned off and receives Link Pulse

F.N

Part Number: TLK105

Hi team,

This customer observes that TLK105 RD± input voltage is ±0.6V when the TLK105 power is
turned off and the TLK105 receives Link Pulse from external HUB device.

This customer thinks that there is a possibility of this state in normal use and the
voltage exceeding the absolute maximum rating -0.3V is a problem.

So, the customer wants to know the TLK105 external circuit to prevent from this overvoltage.
If you have the TLK105 external circuit to prevent from this overvoltage. Please let me know.

Best regards,
Fumio Nakano

over 6 years ago

0 Aniruddha Khadye over 6 years ago

TI__Mastermind 18425 points

Hello Fumio,

Connecting a link partner to TLK105 when the PHY is turned off should not be a problem. Can you share the oscilloscope picture of the waveform coming from the HUB?

-Regards,
Aniruddha

0 F.N over 6 years ago in reply to Aniruddha Khadye

TI__Expert 8760 points

Hello Aniruddha-san,

Thank you for your prompt reply.
Your answer is very helpful.

I requested the oscilloscope picture to the customer.

Best regards,
Fumio Nakano

0 F.N over 6 years ago in reply to F.N

TI__Expert 8760 points

Hello Aniruddha-san,

The customer finally sent me the oscilloscope picture.

Please look at the picture below.

Is this OK?
If it's not OK, could you tell me how to deal with it?

Best regards,
Fumio Nakano

0 F.N over 6 years ago in reply to F.N

TI__Expert 8760 points

Hello Aniruddha-san,

Sorry, the GND level was wrong, so I corrected it.
Please look at the picture below.

Is this OK?
If it's not OK, could you tell me how to deal with it?

Best regards,
Fumio Nakano

0 F.N over 6 years ago in reply to F.N

TI__Expert 8760 points

Hello Aniruddha-san,

Thank you for your cooperation.

How's the situation?
My customer is waiting for the answer.

Best regards,
Fumio Nakano

0 F.N over 6 years ago in reply to F.N

TI__Expert 8760 points

Hello Aniruddha-san,

Thank you for your cooperation.

May I answer the customer that the waveform is okay?

Would you please reply to me ASAP.

Best regards,
Fumio Nakano

0 Aniruddha Khadye over 6 years ago in reply to F.N

TI__Mastermind 18425 points

Hello Nakano-san,

It is ok to keep TLK105 connected to external ethernet HUB even when it is powered off. The -0.3V is DC abs max. Link pulses coming from the link partner will not damage the device.

-Regards,

Aniruddha

0 F.N over 6 years ago in reply to Aniruddha Khadye

TI__Expert 8760 points

Hello Aniruddha-san,

Thank you for your reply.

Your answer is very helpful.
Thank you!!

Best regards,
Fumio Nakano

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TLK105: RD± input voltage when TLK105 power is turned off and receives Link Pulse