DS90C385A: About input equivalent circuit of TxIN pins of DS90C385A

Hiroaki Masumoto

Expert 1210 points

Part Number: DS90C385A

Hi Sir,

I have questions about the input equivalent circuit of the TxIN pin of the DS90C385A.

There is no equivalent circuit description of the input terminal in the DS90C385A data sheet.

There is a description that there is an internal pull-down resistor on the R_FB pin.

As with the R_FB terminal, is the TxIN pins built-in pull-down resistor ?

Is there a problem if putting the TxIN pins in the Hi-Z state for several usec ?

Best Regards,

Hiroaki Masumoto

over 7 years ago

0 Michael Lu (Santa Clara) over 7 years ago

TI__Mastermind 29635 points

Hi Masumoto-san,

Since there is no information explicitly stating that there is a pull-down for the TxIN pins, it must be assumed that they do not have an internal pull-down resistor. There should not be an issue with the TxIN pins remaining Hi-Z for several microseconds.

However, if there are TxIN that will not be used, I recommend tying those unused transmitter input pins to GND.

Thanks,

Michael

0 Hiroaki Masumoto over 7 years ago in reply to Michael Lu (Santa Clara)

Expert 1210 points

Hi Michael-san,

Thank you for your help.
I understand the contents of the reply.
I will inform this information to customers.

Regards,
Hiroaki Masumoto

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DS90C385A: About input equivalent circuit of TxIN pins of DS90C385A