Level conversion with plenty of options

[Andy Brown] wanted one level converter to rule them all, so he set out to build his own which included plenty of options.

The chip at the top and center is a pretty neat little device. It’s an NXP 74ALVC164245DL. In addition to having an incredibly long and seemingly meaningless part number, it contains a pair of bi-directional octal ports. It runs very fast (about 333 MHz) and supports voltages up to 5V on one side, and up to 3.3V on the other. As long as you stay below those maximums you can choose your own target voltages. To do so, he included a couple of adjustable voltage LDOs which are set using jumpers.

But wait, [Andy's] not finished quite yet. If the jumpers don’t offer the target voltage you’re looking for he also included breakout pins so that you may inject the voltage using an external source. He even included the option to use the LDOs on their own, without the level converter. How do you keep all of these configurations straight? He build a little web form that lets you set your desired parameters and it tells you which jumper should be connected.

Comments

  1. HAD says:

    Can it handle PWM to true analog conversion as well?

  2. HAD says:

    THIS is the level conversion device to rule them all.

    http://www.actionio.com/action/ultra-slimpakii/wv408/

    Isolating power supply. Give it 150VDC, honey UltraskimpakII doesn’t give a fuck. It outputs 0-20 mA and scales the output accordingly.

  3. Chris says:

    Love the board, and the IC.

    There was another IC I was looking at, with some equally weird part number, which had automatic direction sensing for each line. Sounds great in theory; but I always wondered if turn-on transients, or an MCU not yet properly software configured, might fool it. I like this much better.

  4. Josh says:

    Great circuit! A future version could offer conversion to serial such as that provided by the max232 (-15v to 15v)

  5. bio says:

    wow amazing! … good find on the IC to it does not seam to be a very popular one by its product name! i was unaware such things existed

    the 5V 3.3V gap gives me headakes all the time … why cant we just stick with one when it comes to hobby stuffs?! D8

    • rasz says:

      its just 74245

      • NewCommentor1283 says:

        yes, a 74_245,
        but with extra input/output recievers/drivers inside

        for prototyping, this module is excellent!

        but for a finished product,
        transistors and resistors will do.(cheaper)

        for prototyping ONLY; i actually would buy one,
        would save hours of useless transistor/resistor soldering! :)

  6. scatterbrained says:

    you have to watch out for ringing with those chips, that fast IO speed combined with some long fly wires will wreak havoc :-(.

  7. Isaac says:

    Level translation is one of the most painful things you have to deal with when designing a circuit if you ask me. Especially when its an external (generally unknown) connection.

    Just recently delved into the world of the autosensing TXS series from TI and it was a complete failure.

    To me, there can’t ever be a one size fits all. And if it doesn’t need to be bidirectional: don’t try and make it.

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