SNVSB79B November 2018 – May 2020 LM25180
The internal bias rail LDO regulator has a lower enable threshold than the converter itself. When VEN/UVLO is above 0.6 V and below the precision-enable threshold (1.5 V typically), the internal LDO is on and regulating. The precision enable circuitry is turned on once the internal VCC is above its UV threshold. The switching action and voltage regulation are not enabled until VEN/UVLO rises above the precision enable threshold.