Abstract: A design of a low-dropout (LDO) voltage regulator with an output current of 800mA is proposed.By introducing a zero-pole tracking circuit with a MOS resistor working in the linear region,the frequency response is independent of the load current.Moreover,with ameliorated miller compensation,a 60° phase margin is guaranteed.Based on the analysis of slewing behavior versus circuit parameters,the load regulation property is improved with a slew rate enhancement circuit which can supply a large current to speed up the slew rate.The precision of the output voltage is maintained within ±60mV under varying load conditions from 800 to 10mA,and the settling time is about 500μs.The chip is implemented in CSMC 0.6μm mixed-signal technology.The designed circuit is validated by the results of the chip test.

Key words: low dropout voltage linear regulator, stability, ameliorated miller compensation, overshoot control