Can I leave inputs and outputs of bidirectional bus buffer open when they are floating?
When bidirectional bus buffers such as 74xxx245 are used, it is necessary that the input level is fixed by external pull-up resistance or pull-down resistance when input/output are floating (high impedance). Unused input/output must always be connected to VCC or GND.
Products with a bus-hold circuit (74VCXH，and 7MPH etc.) do not require external pull-up resistance or pull-down resistance.