JAJSCB0E June 2016 – December 2021 UCC21520
Setting the DISABLE pin high shuts down both outputs simultaneously. Grounding (or left open) the DISABLE pin allows the UCC21520 and the UCC21520A to operate normally. The DISABLE response time is in the range of 20 ns and quite responsive, which is as fast as 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, and it is recommended to bypass using a ≈1-nF low ESR/ESL capacitor close to DIS pin when connecting DIS pin to a micro controller with distance.