A low-noise low-dropout (LDO) circuit with base current compensation is designed in a 180-nm bipolar–CMOS–DMOS (BCD) process. A bipolar junction transistor (BJT) pre-amplifier stage is used in the LDO to reduce the 1/f noise of the error amplifier. A unity-gain negative feedback architecture is utilized to eliminate the noise generated by the feedback resistor network, and a first-order RC low-pass filter is used to attenuate the high-frequency noise of the reference. Additionally, a base current compensation circuit is proposed to compensate for the base current of the BJT pre-amplifier stage, thereby preventing the decrease in the reference voltage. Simulation result shows that the LDO has an input voltage of 2.4–5.5 V, output voltage of 0.8–5.3 V, and maximum load current of 500 mA. The output noise spectral density at 1 kHz is 4 nV/{L-End}$\sqrt{\text{Hz}}$, and the integrated noise from 10 Hz to 100 kHz is 0.92 μV_RMS.