An LDO regulator is arranged to provide regulation with a pass device, a
cascode device, a level shifter, an error amplifier, and a tracking
voltage divider. The error amplifier is arranged to sense the output
voltage and provide an error signal to the pass device via the level
shifter. The level shifter changes the DC level of the error signal such
that the pass device is isolated from damaging voltages. The cascode
device is arranged to increase the impedance between the output node and
the pass transistor such that the LDO regulator can sustain input voltages
that exceed process limits without damage. The cascode device is biased by
the tracking voltage divider. The tracking voltage divider adjusts the
biasing to the cascode device such that a decreased input voltages result
in lower impedance, and increased input voltages result in higher
impedance.
