SN74CB3Q3253: unused pin setting OE

The 2OE pin must not be left open. To disable channel 2, connect it directly to VCC.

Hey Frank,

As Clemens mentioned, It's good practice to give the OE pins a known state. Here it's better to just disable 2OE by running it high and holding that state. By floating the pin the floating pin can pick up noise (it's essentially an antennae now) and will fluctuate somewhere between it's high state and low state. From a functional stand point, you may see the same results on your Vi/o line that you're using. However, from a holistic view, keeping the OE pin floating of the unused channel will essentially give you a condition where both high-side and low-side of the FET are simultaneously turned on resulting in a current spike. 

Is there a reason they're still using the SN74CB3Q3253? We have 1 channel 4:1 IC's such as the TMUX1204 which is a low-Ron general purpose multiplexer that comes with fail-safe logic and looks to be a cheaper alternative to the 3253 device. 

Thanks,
Rami