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SN74CBTLV1G125: question on the DATASHEET

Azza Boutour
Prodigy 80 points
Part Number: SN74CBTLV1G125

Hi,

I have a question regarding this part,

The datasheet specifies a VinHighMin of 2V when supplied at 3V3.

We assume the A to B connection are 2 FET switches so it should not care about high or low as it is just an analogue connection. The VIN levels should only be applicable on the OEn input, but the datasheet is not clear on that.

Are these assumptions correct and can we connect an LVCMOS18 signal to the A-port of the device?

The device will be supplied by 3V3, OEn will be tied to GND.

Thanks and regards.

--

  • 0
    TI__Genius 9132 points

    Hi Azza,

    Are you referring to VIH and VIL in the Recommended operating conditions?

    The OE# pin threshold voltage range is defined by the VIH and VIL specs in the datasheet. It determines if the switch turns on or off if the control signal is low or high.

    Can you provide some more details/block diagram how you are connecting an LVCMOS18 signal  using the SN74CBTLV1G125? What is the signal voltage for  LVCMOS18  you are trying to pass?

    Thanks

    Saminah

  • 0
    Guru 276360 points

    This device is an analog switch; the A and B pins indeed allow any voltage.

  • 0 in reply to Saminah C
    TI__Prodigy 80 points

    Here are the answers to your questions:

    Are you referring to VIH and VIL in the Recommended operating conditions?

    Yes.

    The OE# pin threshold voltage range is defined by the VIH and VIL specs in the datasheet. It determines if the switch turns on or off if the control signal is low or high.

    So the thresholds don’t apply to the A and B pins?

    Can you provide some more details/block diagram how you are connecting an LVCMOS18 signal  using the SN74CBTLV1G125?

    It’s a point-to-point connection from LVCMOS18 driver to SN74CBTLV1G125 port A and also from SN74CBTLV1G125 port B to a LVCMOS18 receiver. No ODs or PUs or PDs.

    What is the signal voltage for  LVCMOS18  you are trying to pass?

    Voh = 1.45V

    Vol = 0.45V

    Vih = 1.2V

    Vil = 0.65V

     

  • 0 in reply to Saminah C
    TI__Prodigy 80 points

    Hi,

    Can you please answer my questions, I replied back with the answers that you asked for.

    Kind regards,

    --

  • 0 in reply to Azza Boutour
    TI__Genius 9132 points

    Hi Azza,

    Thank you for providing the details.

    Your understanding is correct. The VIH and VIL specs apply to logic pin OE and not to A or B. A and B are the I/O pins.

    The input voltage for the SN74CBTLV1G125 is 0V - 3.6V.

    Your signal voltage is within this range so the SN74CBTLV1G125  looks like a good fit.

    Thanks

    Saminah