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  • TI Thinks Resolved

TPD5S116: I2C read and write fail

Part Number: TPD5S116

Hi  TI ,

    I used TPD5S116 in my design ,using its  I2C  level shift function ,when HDMI cable connect   TV ,LT8912 I2C  read fail ,but  TV I2C read is OK ,could you please check what is the rootcause ?how can i solve it 

Schematic is following

thanks

peiyuanqing 页面提取自-splendor_bottom_board_v01_20180.pdf

  • Hi, peiyuanqing,

    I am working on it, I will reply you early next week.

    Regards,
    Bob
  • Hi, Peiyuanqing,

    I have asked help from teammates. Please kindly wait.

    Regards,
    Bob
  • In reply to Bob Ma:

    Hi Peiyuanging,

    The TPD5S116 has a very tight specification on VIL for SCL and SDA on the system side.  Does you system meet these specifications?  If you MCU or HDMI source does not, I can recommend an I2C level shifter that will meet this specification.

    Please let me know if I can help further.

  • In reply to Chuck Branch:

    Hi Quote,

           we change to TXS0102 ,it works well, i'm  confuse .we use 1.8V as VCCA  in TPD5S116 ,0.082*1.8 ,  0.15V is the max of VIL ,  datssheet of  TXS0102 is 0.15V too ,how it works?

    thanks

    peiyuanqing

  • In reply to user5351860:

    This can happen when one design has better margin to the specification than another. The level shifter that you selected has an absolute 0.15V VIL. The TPD5S116 is relative to the power supply. If the supply is lower than 1.8V, say 10% because of noise, IR Drop, and regulator error, then you will have 1.62V on VCCA and will fail specification.

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