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  • How To Create Logic level Converter ?

    Abhishek Rawal

    Abhishek Rawal

    @abhishek-fg9tRh
    Updated: Oct 24, 2024
    Views: 1.3K
    If you have ever tried to connect a 3.3V device to 5V system, you know how much mindfudge it can be.

    So, now I am thinking of creating a logic level converter which steps down from 5.0V to 3.3V & Steps up to 3.3V to 5.0V easily.
    I wanna know : HOW ?
    (No, I don't wanna buy readymade LLC from Sparkfun, so please don't suggest that)

    Just help me by giving me good detailed Circuit diagram & I will take care of PCB-Layout & rest of the stuffs.

    Thanks, In advance.
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  • Abhishek Rawal

    Member • Jun 15, 2013

    :BUMP:
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  • Harshad Italiya

    Member • Jun 15, 2013

    Best option is to use level shifter IC. For example SN74LVC245A from Texas Instruments.

    BTW which tool you are using for PCB designing?
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  • Abhishek Rawal

    Member • Jun 15, 2013

    Eagle & sometimes gplEDA.

    #-Link-Snipped-# Can you enlighten me more about Level shifting ?

    -Edited the post & tagging Godfather, so he can help me out-
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  • Harshad Italiya

    Member • Jun 17, 2013

    Abhishek Rawal
    Eagle & sometimes gplEDA.

    #-Link-Snipped-# Can you enlighten me more about Level shifting ?

    -Edited the post & tagging Godfather, so he can help me out-
    Will you please tell me what exactly you want to know about level shifting?
    You can also use simple resistor-divider network to interface 3.3V device with 5V device.
    Here is one Example:-
    [​IMG]
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  • Abhishek Rawal

    Member • Jun 17, 2013

    I just want to make logic level converter from 5 to 3.3 & 3.3 to 5 dual-way,On my own.
    I wanna use it to control arduino based robot with ps2 controllers as they need 3.3V
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  • Harshad Italiya

    Member • Jun 19, 2013

    Abhishek Rawal
    I just want to make logic level converter from 5 to 3.3 & 3.3 to 5 dual-way,On my own.
    I wanna use it to control arduino based robot with ps2 controllers as they need 3.3V
    Well, I understand that you want to make level converter in dual way but are you sure that pin you are using is configured either in INPUT or in OUTPUT mode.

    If you are using your arduino pin as output it will swing between ground and 3.3v and I think device you are connecting will consider 3.3V as HIGH logic only.
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  • Abhishek Rawal

    Member • Jun 19, 2013

    Harshad Italiya
    Well, I understand that you want to make level converter in dual way but are you sure that pin you are using is configured either in INPUT or in OUTPUT mode.

    If you are using your arduino pin as output it will swing between ground and 3.3v and I think device you are connecting will consider 3.3V as HIGH logic only.
    Imma check on this & get back to you, ASAP !
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  • arunchary

    Member • Jun 19, 2013

    i think MAX232 or ST232 level converter ic may help us to convert the 3.3v signal to 5v or vice-verse.
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  • Harshad Italiya

    Member • Jun 19, 2013

    arunchary
    i think MAX232 or ST232 level converter ic may help us to convert the 3.3v signal to 5v or vice-verse.
    #-Link-Snipped-# No !
    MAX232 and ST232 are used to convert voltage level between RS232 and TTL. RS232 logic level swings between -15V to +15V so you can not use the same for 3.3V-5V level converter.

    I haven't come to know about any bidirectional level converter. Level converter are mostly unidirectional.
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  • arunchary

    Member • Jun 19, 2013

    Ok ,i got the point, so FET can do this conversion and also the ic called 74Lxx245
    here is the circuit of FET
    #-Link-Snipped-#
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  • Harshad Italiya

    Member • Jun 19, 2013

    arunchary
    Ok ,i got the point, so FET can do this conversion and also the ic called 74Lxx245
    here is the circuit of FET
    #-Link-Snipped-#
    Please move this file to your public folder and share it's link. Above link asks for user-id and password.
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  • arunchary

    Member • Jun 19, 2013

    here is the link for the circuit
    <a href="https://www.dropbox.com/s/a8r7uzi97dy0cwt/mosfet_level_converter.jpg" target="_blank" rel="nofollow noopener noreferrer">Dropbox - mosfet_level_converter.jpg - Simplify your life</a>
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