Comments: Bi-Directional Logic Level Converter Hookup Guide


Comments 3 comments

  • I would like to use this board to run the 3,3V inputs of the Tsunami PCB. The thing is that I would only need it to be uni-directional, converting a higher voltage to the lower 3.3V level. I wish to use this with a Eurorack Synthesizer system and unfortunately, the gate levels used by the different module makers vary anywhere from +5V to almost +12V. What High reference voltage (HV) should be plugged into the Bi-directional converter board that would allow it to work across a wide range of input voltages. Remember, I don’t need to OUTPUT a HV level at all, just be able to connect a gate voltage there that may range between +5V to +12V and produce the 3.3V gate needed for the Tsunami.

  • What is the upper limit of the high side?

    I note the application note discusses a high voltage section, VDD3, but it doesn’t specify an upper limit. Would I be correct in assuming the Vds on the mosfet (50V in the case of BSS138 as used here) is that limit?

    Specifically I wish to use a high voltage rail for communicating I2C over long distances with potentially high noise, most likely using CAT5E cables. My application has both 12V and 48V available in addition to logic level rails.

  • I think in the I2C example you need to add 10k pullups on the SDA and SCL on both sides of the level shifter as I2C is O/C

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