For proper LDO operation, the input voltage should always be higher in magnitude than the output voltage When an input voltage is applied, the low-drift, bandgap reference voltage is established. The bandgap voltage and an op amp are used to sense the resistor divider voltage at the output. This divider establishes the output voltage magnitude. Regardless of input voltage as long as it remains higher than V^sub DROPOUT^ + V^sub OUT^, the output voltage will stay constant.