Abstract: A low-drop out (LDO) regulator is provided. In one embodiment, the LDO regulator includes an error amplifier, a pass transistor, a reference voltage circuit, an output noise filter, and a voltage divider. The voltage divider provides a feedback voltage based on the output voltage. Further, the feedback voltage is provided at a feedback node. The output of the error amplifier is coupled to the pass transistor. The reference voltage circuit is coupled to a first input of the error amplifier. The output noise filter is coupled between the feedback node and the second input of the error amplifier.

Abstract: A circuit and method for providing voltage regulation that operates with relatively low noise, low power, fast start up and low dropout. The invention includes a constant voltage reference that is coupled to a reference amplifier which amplifies the reference voltage to a selectable level. The output of the reference amplifier is provided to an integrated low pass noise filter which suppresses at least the noise generated by the constant voltage reference and the reference amplifier. The output of the integrated noise filter is provided to the inverting input of an error amplifier, whose non-inverting input is coupled to the output voltage (VOUT). Also, the output of the error amplifier is coupled to a gate of a pass transistor that is coupled between the input voltage (VIN) and the output voltage (VOUT) of the invention.