• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 391 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

AM26C31: Question about a differential input voltage of AM26C31(RS-422 Driver).

user5233567
Prodigy 170 points
Part Number: AM26C31
Other Parts Discussed in Thread: , AM26LV31E

Hi there, 

I am designing an RS-422 interface that requires lightning protection using the AM26C31.

To select TVS for lightning protection,the maximum input voltage information for the Output X pin of the AM26C31M is required.

In this regard, I have two questions.

1. On the data sheet, which of the maximum input voltage for output x pin(differential pair) is Vi(input voltage) or Vid(Differential input voltage)?

    I think Vid is the maximum input voltage for output x pin. is it correct?

2. If Vid is right, can one pin of the differential pairs withstand up to 14V when another pin of the differential pairs is 0V?

I will wait for your answer.

Thanks.

  • 0
    TI__Mastermind 25705 points

    Hi,

    Sorry I have to make some correction in my original reply.


    Thanks for reaching out to us.
    1. The way of your understanding is kind of correct. Actually Vid doesn't make sense for AM26C31 since the device doesn't have any differential inputs. But you can consider using this abs max specifications for Vo range (single-ended).
    2. Yes. Each pin can stand up to +-14 V individually.
    Please let me know if you have more questions.

    Regards,
    Hao

  • 0 in reply to Hao L
    Prodigy 170 points

    Thank you for the reply.

    I have additional questions.

    I can understood that the maximum input voltage that AM26C31M's output pins can withstand is Vid(Input Differential Voltage, +/- 14V) because of your answer.

    For an AM21LV31E-EP driver that do not provide Vid information on the data sheet, is the maximum voltage that output pin can withstand is Vin?

  • 0 in reply to user5233567
    TI__Mastermind 25705 points

    I'm sorry I didn't make it clear enough. AM26C31, AM26C31M and AM26LV31E are all line drivers, which has one digital input and differential output for each channel. Therefore Vid (differential input) spec doesn't apply here. If you see Vid on the datasheet, it would be typo. What we should be looking for is Vo spec. With this information, the abs max Vo of each device is:
    AM26C31: -0.5V to +7V
    AM26C31M: -0.5V to +7V
    AM26LV31E: -0.5V to 6V
    Please let me know if it makes sense to you.

    Regards,
    Hao