• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 33 subscribers
  • Views 210 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN75162B: How to configure unused pins

Shinichi Inoue
Guru 21721 points
Part Number: SN75162B
Other Parts Discussed in Thread: SN75176B

Tool/software:

Dear Specialists,

My customer is considering SN75162B and has questions.

I would be grateful if you could advise.

---

I have 2 questions regarding SN75176B.

Could you please advise?

(1)  Is there a possibility of malfunctions if the terminal side of signal lines such as SRQ, DAV, and NDAC are connected to GND and the BUS side is left open?

(2) Could you please tell me how to handle unused pins?

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Guru 52462 points

    Hi Shinichi,

    Are you asking your question about the SN75162B or the SN75176B - they are very different parts - one is a GPIB transceiver the other is RS-485; completely different standards - so which part are you asking the question about. 

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Guru 21721 points

    Hi Parker,

    Thank you for your reply.

    This is a question about SN75162B, the customer is considering GPIB.

    SN75176B is a typo. I'm sorry.

    Could you please advise how to configure unused pins about SN75162B 

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • +1 in reply to Shinichi Inoue
    TI__Guru 52462 points

    Hi Shinichi,

    No problem - I just wanted to make sure I was looking at the right thing because unused pins are treated differently for each device. 

    For the first question. 

    For SRQ, DAV, and NDAC you shouldn't leave the pins floating on the bus side - if these are unused ground all of them both terminal and bus side. The reason being that if the logic control of the IC puts the receiver active (bus to terminal data flow) the receiver will be open circuited and the voltage is undefined which could lead to glitching and supply current fluctuations which could be problematic at a system level. 

    For the second question:

    If the port in application is always an output and never an input you can leave it floating - if the pin may be turned into an input due to the logic control of the device it should be grounded or tied to VCC - essentially it is best practice to just ground all unused pins for this device to avoid issues. 

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Guru 21721 points

    Hi Parker,

    Thank you for your reply.

    I'll share your answer with the custoemr.

    When they have an additional question, I consult you again.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi