SLUSCV6A April 2017 – February 2018 UCC21225A
Setting the DISABLE pin high shuts down both outputs simultaneously. Grounding (or floating) the DISABLE pin allows UCC21225A to operate normally. The DISABLE response time is in the range of 20ns, limited only by the propagation delay. The DISABLE pin is only functional (and necessary) when VCCI stays above the UVLO threshold. It is recommended to tie this pin to ground if the DISABLE pin is not used to achieve better noise immunity.