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TPD12S016 I2C level shifter

Tomasz Musialik
Prodigy 20 points
Other Parts Discussed in Thread: TPD12S016, TPD4E05U06, TPD5S116

Is it possible to build HDMI repeater using TPD12S016 chip on input and output. I noticed the problem regarding I2C level shifter - on input side after level shift signals (SDA_A and SCL_A) will have low level Vola=Vcc*0.17, but on output side it request low level Vila=0.082*Vcc. It means that it will not work, am I right ? Do you have any easy solution of this problem ?

Best regards,

Tomasz Musialik

  • 0
    TI__Genius 12190 points
    Hi Tom,

    TPD12S016 is not 5V tolerant on the A side. Take a look at TPD5S116 which is, though it offers no protection for the TMDS. They can be protected by TPD4E05U06.
  • 0 in reply to Guy Yater
    Prodigy 20 points

    Dear Yater,

    Thank you for your reply. But I think this is a little bit misunderstanding. My question was, that if we use TPD12S016 on the input (B side external and A side to the "HDMI Repeater") and TPD12S016 on the output (A side to the "HDMI Repeater" and B side external) then there was a problem with I2C low level on A sides both. I mean on input side of "HDMI Repeater" level shifter (SDA_A) gives 0,56 V for low level (Vcc=3,3 V), but on output side of "HDMI repeater" SDA_A requires low level <0,27 V. Please find attached simplified schematic.

    Best regards,

    Tom

  • 0 in reply to Tomasz Musialik
    TI__Genius 12190 points

    Hi Tomasz,

    Is there a repeater between the two TPD12S016, or are they connected as shown in the schematic above? If as shown in the above schematic, then the Vol will be higher for the DDC/CEC/HPD lines due to their internal 10k pull-ups being in parallel with each other. The same thing can happen if there is, in fact, an HDMI repeater between the two: if there is any pull-up external to the TPD12S016  DDC/CEC/HPD lines then the Vol will be higher on the A-side, due to the TPD12S016 sinking that much more current, raising the voltage drop across the sink that pulls down the line.

    Regards,