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SN74LVC8T245

Ehud Sumazin
Prodigy 10 points
Other Parts Discussed in Thread: SN74LVC8T245

Hello,

I would like to know if I should connect the expose pad of the SN74LVC8T245 in RHL package to GND or to other surface.

And I would to know if there is a reference design.

Best regarsd,

Ehud

  • 0
    TI__Genius 9085 points

    Hello,

    The exposed pad can either be connected to a PCB pad connected to ground, or a PCB floating (not electrically connected) pad.

    I am not aware of any reference designs for this device. If there are any specific questions about designing with this device, please post them here!

  • 0 in reply to Hattie
    Prodigy 120 points

    Hi,

    Thanks

    I have checked the connectivity using DMM. PCB PADs are connected IC and no short between GND.

    If Connect 5V to the pin through pullup. The Voltage is reaching 1.6V and it is not exceding.

    Thanks and Regards,

    Sankar.K

  • 0 in reply to Sankar karuppannan
    TI__Genius 9085 points

    You should NOT connect the center pad of the IC to VCC.

    Though the pad is not connected to GND internally in the IC, GND is the prefered connection. You can also connect the center pad to a floating pad on the PCB, a pad with no electrical connection.

     

  • 0 in reply to Hattie
    Prodigy 185 points

    The issue we encountered with SN74LVC8T245 is once the board is powered up, there is a pulse ~ 200us to 5V at port B. We didn't connect /OE to Vcca but we connect it to GND instead. Although the datasheet did advise to pull /OE to high to Hi-Z on both ports during power up and down. We are not doing so as to save one control line. The 5.125V supply comes up first then 3.3V at 20ms later. Port A signal are all low with 10k ohm pull to gnd. Would like to an advise from TI whether it's a must to pull /OE to high in order to eliminate the pulse at port B during power up. Thanks.