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SN74LVC1T45-EP: SN74LVC1T45-EP

Evgeny Vaintraub
Prodigy 50 points
Part Number: SN74LVC1T45-EP
Other Parts Discussed in Thread: SN65HVD233-EP, , SN74LVC1T45

Tool/software:

Hi,

I use Can Bus transceiver PN -  SN65HVD233-EP  which is connected through a level converter - SN74LVC1T45-EP to FPGA , as shown in the attached drawing .

A level converter side VCCA powered by voltage 2.5V and pin 3 on the device - SN74LVC1T45 connect to FPGA to bank powered from 2.5V  , pin 4 of level converter connect to Can Bus transceiver pin 1,

My question is what happens to the output of a level converter pin 4 that connects to the Can Bus pin 1 while the VCCA voltage starts to rise from 0 to 2.5 until the 2.5V voltage stabilizes ?

My suspicion is that until the 2.5V voltage stabilizes, the logic level at the output of the Level Converter component will be in a random state that could disrupt the Can Bus ?

My assumption in this question is that the 3.3V - VCCB  of level converter is stable at this time.

Thanks,

Evgeny

  • +1
    Prodigy 50 points

    One more question please:

    What will happen if the VCCA voltage is stuck at 1V, what logic level will be at the output of level converter?

    Is it in such a situation CAN BUS can get stuck?

  • 0
    TI__Genius 9140 points

    Hello Evgeny,

    There shouldn't be any issues with VCCA powering up after VCCB.  Additionally, the input pin is pulled-up to VCCA so the logic level at the output will also be logic High.

    It's possible the bus could get stuck since the voltage supplied is lowered than the recommended minimum voltage (1.65V)

    Regards,

    Josh