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SN74LVCH16T245: SN74LVCH16T245

Jani Isoo
Intellectual 1930 points
Part Number: SN74LVCH16T245

Hi,

I am looking at the TI part SN74LVCH16T245. This part states in the datasheet that: “ to ensure high-impedance state of the outputs during power up or down, the OE pin must be tied to VCCA through a pullup resistor and must not be enabled until VCCA and VCCB are fully ramped and stable”.

  

   Due to the above statement, I need to know what state the outputs or ports would have if VCCA ramps up before VCCB and vice versa. Is there any risk of glitches or unknown states if VCCA and VCCB ramps at different times and the ports are enabled?

  

Thanks,

Jani

  • 0
    TI__Intellectual 2100 points
    Hey Jani,

    This part is designed to have the two supplies track each other (start the ramp at the same time) but I don't expect there to be any issues if OE is strapped to Vcca and it rises first. In the other direction I don't expect it to have much, if any major glitching but I would try to ensure the proper power sequencing since it is how the part was intended to be used. A good portion of customers actually tie OE to GND so they don't have to use a GPIO on a simple enable, which although not to spec, works just fine for them.

    If this answered your question please hit the green verification button below to know that we could help you out! If you have additional questions feel free to send them along and I will answer them as quickly as I can for you.

    Best Regards,
    Nick