• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 32 subscribers
  • Views 420 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.

LM63: SMBus question

Allan Fan
Expert 7080 points
Part Number: LM63

Hi Expert,

May I know if LM63 support SMBus v3.0 or v3.1? And how do we come out 300ns minimum data hold time spec?

Thanks.

Allan 

  • 0
    TI__Guru* 91206 points

    Dear Allan - 

    Thanks for posting on E2E. The LM63 was released in 2002 and has a two wire interface which is compatible with v2.0 of the SMBus specification as the max clock speed is 100kHz. This means it is compatible with v3.0 and v3.1 in the sense that those specs appear to be backwards compatible with previous ones.

    The v3.0 of SMBus (released in 2014) introduced 400kHz and 1MHz bus speeds to this protocol along with some new protocols for reading and writing 32 and 64 bit values and support for lower nominal VDD of 1.8VDC. v3.1 is more or less identical to v3.0, with the exact change / new additions listed on pages 81 and 82 of the spec itself. http://www.smbus.org/specs/

    The hold time spec is described as now being a copy of the I2C spec, because the SMBus working group realized the I2C spec was what the industry was following (see pages 83 - 84 of the v3.1 spec)

     

  • 0
    Prodigy 10 points

    Hi Josh,

    Thanks for your great answer!

    LM63 can compatible with SMBus v3.0 and v3.1. right? So can we take SMBus v3.0 or v3.1 specification to view LM63 AC timing? Because the data hold timing is 58ns on our board. I'm not sure whether LM63 have any side effect in the design?

    Regards,

    Bob

  • 0 in reply to Bob Teng
    TI__Guru* 91206 points

    Bob - 

    Any update made to the v3.0 and v3.1 that are not covered by v2.0 are not supported by the device, as it was released before those specs.

    You will have to see if the hold time is an issue or not with your system. Generally it should not be, but you do need to check on your side.

  • 0 in reply to Josh Wyatt
    TI__Expert 7080 points

    Hi Josh,

    Do we have newer solution meet v3.1 or don't like LM63 require 300ns minimum data hold time?

    Thanks.

     

  • 0 in reply to Allan Fan
    TI__Expert 6820 points

    Hi Bob,

    We do not have any newer fan controllers that meet SMBus v3.1.  

    Thanks,