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SN74AVC8T245-Q1: Logic forum

Part Number: SN74AVC8T245-Q1

To whom it may concern - 

In the datasheet, it states that "To ensure the high-impedance state of the outputs during power up or power down, the OE input pin must be tied to VCCA through a pullup resistor and must not be enabled until VCCA and VCCB are fully ramped and stable."

In the design, if we choose to pull OE to gnd, does that mean during power up/power down, the I/Os are not high impedance? Is there any concern of damage, if the part is being driven into the IOs, but VCCA/VCCB = 0V?

Thanks

  • When VCC = 0 V, all I/Os are high impedance.

    The only danger is that, when the supplies are above zero but below the recommended minimum, that DIR or data inputs do not work correctly, and that some outputs drive the wrong value and/or on the wrong side. Your circuit must be able to handle that.