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Bus voltage translation

Discussion in 'Electronic Design' started by Steve Minshull, Jul 25, 2006.

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  1. Hi

    What IC (or IC family) would you guys recommend for translating from a
    3.3V logic level to 5V logic level? I have 3.3V logic on a DSP board
    and 5V CMOS logic on a connecting daughter board. It's a 16 bit bus.

    Thanks in advance

    Steve Minshull
     
  2. PeteS

    PeteS Guest

    What speed are you running the interface at?

    Is each signal unidirectional?

    If they are all unidirectional signals, and the 5V board has TTL
    compatible inputs, you don't need to do anything from the 3.3V -> 5V
    domain.

    In the other direction, you can either use a device with 5V tolerant
    inputs (most of the 74AHC range) or just use a resistive divider for
    relatively slow signals.

    If everything's high speed, then a translator may be better

    Here's TI's offerings - others (Philips, Fairchild, OnSemi) make them
    as well

    Dual supply:
    http://focus.ti.com/paramsearch/doc...avigationId=11385&family=logic&paramTable=yes

    Single supply:
    http://focus.ti.com/paramsearch/doc...avigationId=11385&family=logic&paramTable=yes

    Translating bus switches if you have bidirectional signals:
    http://focus.ti.com/paramsearch/doc...avigationId=11385&family=logic&paramTable=yes

    Cheers

    PeteS
     
  3. John Larkin

    John Larkin Guest

    SN74ALVC164245 is an absurd part number, but it works fine.

    John
     
  4. Cheers for the help

    I've found a dual supply bus translator from fairchild which should do
    the job.

    Steve Minshull
     
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