DS15MB200: Bypass differential signal when no VDD supply

Kay Chen53

Part Number: DS15MB200

Hi there:

I'd like to check about DS15MB200 whether has the bypass function when no VDD supply? due to we only could find the pre-emphasis control pin and presume the input differential still could output thorough.

Please correct me if there is any misunderstanding.

over 6 years ago

0 Kay Chen53 over 6 years ago

Expert 2225 points

update application for two RJ-45 port communication

0 Michael Lu (Santa Clara) over 6 years ago in reply to Kay Chen53

TI__Mastermind 29655 points

Hi Kay,

Can you provide an example of what you mean by "bypass function when no VDD supply?" Are you asking about whether the device can act like a passive switch when VDD is not provided?

Thanks,

Michael

0 Kay Chen53 over 6 years ago in reply to Michael Lu (Santa Clara)

Expert 2225 points

Hi Michael:

not sure whether you could read the original message with this, but mostly like when the case is VDD not provided

0 Michael Lu (Santa Clara) over 6 years ago in reply to Kay Chen53

TI__Mastermind 29655 points

Hi Kay,

Thanks for the background information.

If VDD is not provided, then the DS15MB200 will not output a signal. Although there is an internal 100-Ohm differential termination, the VDD supply is still needed to power the receive buffer and output driver. There is no "passive" bypass function.

Regards,

Michael

0 Kay Chen53 over 6 years ago in reply to Michael Lu (Santa Clara)

Expert 2225 points

Hi Michael:

Thanks again!~ We also get the idea from customer for further requirement.

If DS15MB200 couldn't achieve this requirement, would you help to advice other solution for customer?

P.S they don't want to use the relay to design this. So they're prefer using the Mux or switch function solution.

0 Michael Lu (Santa Clara) over 6 years ago in reply to Kay Chen53

TI__Mastermind 29655 points

Hi Kay,

I looked through our portfolio of switches, and even the passive FET switches in our portfolio still require VCC power to be supplied to the switch device in order to function properly. I do not think we have an IC where there is a "bypass" function in which the switch operates when no VCC power is supplied to the switch.

In normal operating conditions, where does the customer's switch board derive power? Is it from a separate power supply, or are they implementing PoE? If PoE is used, then perhaps a voltage regulator can be used to provide the appropriate power supply to the switch IC (such as the DS15MB200) when a valid connection is made to the RJ45 connectors.

Thanks,

Michael

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DS15MB200: Bypass differential signal when no VDD supply