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Looking for an IC that will convert 3.3v PWM(bit-banging) to 5v signal that can also be able to drive 50-100ma

Other Parts Discussed in Thread: TXB0108, LSF0108, TPL7407LA, SN74LVC8T245

Hello TI Team!

I was wondering if you could please help me with an issue I am facing. I am trying to find an IC for a project I am building the requirements are converting 3.3v to 5v and 5 v to 3.3v, able to handle the out to drive a peripheral min 30mA ( would be nice to have a safety of 30% ) for 2 lines (HIGH/LOW)  and rest would be around 15mA  PWM (bit-banging) signal, would have about 30 lines of these, so multiple chipsets would be okay.

I have looked at TXS0108 and TXB0108, as well as LSF0108 but seems to be having a voltage drop one we attach a load to it so it is not able to get a clean 5v out.

any help would be appreciated.

thank you,

Joichi

  • Joichi,

    Are you trying to drive a load?

    The TXB and LSF devices you listed are for level translation between two ICs trying to communicate to each other, not for intentionally driving current through to turn something on/off.

    It sounds like you may be looking for some kind of buffer device. My first thought would be an op amp set up in a unity gain mode (https://www.ti.com/amplifier-circuit/op-amps/power/products.html)

    -Bobby

  • Hello Bobby!

    Thank you for the reply, Yes I was reading that, it should be between chipsets. With reading the continuous current output I thought I would be able to get away with it. 

    Yes, I am trying to drive a load. Is there an IC that is multiple circuits with a low propagation delay? 

    would an op-amp have a less propagation delay than a MOSFET ic?

    Thank you

    Joichi 

  • Auto-bidirectional level shifters cannot drive a load, because they do not know which side is the source and which is the load.

    Do you actually need to change the direction for any single line? If yes, would it be possible to have a separate direction signal? (Something like the SN74LVC8T254, or multiple smaller LVC translators, might be helpful).

  • very interesting, Thank you  

    Now I am looking at TPL7407LA. I will make it with 2 chipsets. One for going from 3.3v to 5v and another for 5v to 3.3v, Just want to confirm this is possible. 

    what would be the pro and cons of these other chips?

    SN74LVC8T245

    ULN2803A

    Thank you,

     

    Joichi Mochizuki

  • Low-side drivers like the TPL7407LA and ULN2803A do not output a high-level signal. Do you actually need to drive a high voltage, or do you need drivers that can tolerate the high voltage when off?

    Please show a schematic of the desired circuit.