I'm considering using the SN74ALVC245 8 bit transceiver in an application between a CPU and some other devices.
While researching a possible alternative to this part I came across the higher output SN74LVCH8T245, which in addition to advising the provisioning of OE as desired for startup, warns that because the inputs are always on, regardless of the state of OE, they cannot be left floating and therefore must be pulled up / down. I assume this is for the usual reason: excessive current consumption near the CMOS P/N thresholds.
My issue:
On reset my SoC configures all of its pins as inputs (highz). I have no control over this and would really prefer to avoid adding pullups (even weak ones) to every input for the usual reasons (cost, power). I do have one pullup on the OE line that is driven by a GPIO and I expect that GPIO to go highz during reset as well, but in this case the OE will float to 3.3V and disable the transceiver outputs.
Questions:
1) Despite the fact I see no such warning in the SN74ALVC245 8 bit transceiver datasheet, does the same restriction about "no floating inputs" apply? In other words, is there any risk to excessive power consumption / undesired behavior with the transceiver when the CPU outputs go highz?
2) Does having OE enabled or disabled change anything? Is the device inherently "safe" if the outputs are disabled?