• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 19 subscribers
  • Views 487 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.

SN74LVC125A: Need SPI and PCM bus buffer

Paul Yeh
Genius 13625 points
Part Number: SN74LVC125A
Other Parts Discussed in Thread: SN74AUC125, SN74AUC34

Hi team,

My customer is asking SPI and PCM BUS's buffer because their chip signal's layout trace is too long.

So they need buffer to increase the driver capability.

I just choose this part but not sure it is ok or not.

the spec. they need is VCC=1.8V and it seems clock rate is 8.192MHz.

Thanks

  • 0
    TI__Guru* 96591 points

    Hi Paul,

    If the concern is improving signal integrity, I think we can help, but I'll need more info.

    When you say that the trace is 'too long' -- how long is it? What's the impedance? What's the load?

    Has the system already been built and they saw issues with signal integrity? If so, I'd like to see scope shots & get more details on the system.

    If not, has there been a signal integrity simulation done? If so, can we see that?

    Any details I can get would help.  

  • 0 in reply to Emrys Maier
    TI__Genius 13625 points

    Hi,

    Based on customer's feedback, they only told me their length is around 25cm and should no impendence problem.

    And they find there is similar Q&A in E2E for this device. So they would like to know is this device can use or not.

    And for clock rate, they need higher for more signal quality margin.

    Please advise.

    Thanks

  • 0
    Guru 243980 points

    LVC is optimized for 3.3 V. At 1.8 V, it supports only 40 MHz.

    You should use AUC family devices, e.g., SN74AUC125 or SN74AUC34, which support 125 MHz. Furthermore, AUC outputs have additional features to improve signal quality.