Comments: Bi-Directional Logic Level Converter Hookup Guide


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #1161427 / about 3 years ago / 1

    The examples in the guide are all for a 5v Arduino and devices attached that need 3.3V. It would be helpful to also have an example of an arduino with a 3.3V output and something that needs 5V, like an IR sensor or addressable LEDs.

  • Member #628687 / about 3 years ago / 1

    As a best design practice, should I use pull-up resistors with a level shifting in I2C lines?

  • Member #628687 / about 3 years ago / 1

    Hi there If I'm to use pull-up resistors in both sides (3.3v and 5v sides) of the I2C line, I should only consider a level shifting and or else disable Atmel328p input pull-ups of I2C lines and use without pull-up resistors and level shifters?

  • Member #1531487 / about 5 years ago / 1

    does this converter support analog inputs? like in case if i need to convert 0-5v analog input to 0-3.3v analog output or vice versa , would it be possible with this logic converter ?

  • wizhippo / about 5 years ago / 1

    Note these have limited current and cannot drive devices such as an SSR-40 DA.

  • Member #1285793 / about 6 years ago / 1


    How would I go about determining the max baud rate supported for UART here? Hoping for 115200+ with a 3.3v to 3.6v UART level shift.

    Thanks for the help!

  • Member #609079 / about 7 years ago / 1

    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.

  • Member #665197 / about 9 years ago / 1

    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.

  • Member #327692 / about 9 years ago / 1

    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

If you've found an issue with this tutorial content, please send us your feedback!