| The extensive application of portable equipments and the quick development of computer, communication and automobile etc. results of the continuous development of LDO linear regulators. The characteristic of super low dropout voltage and super low consumption as well as the output capacitor free frequency compensation have become the main research direction of LDO technology. This thesis will provide a kind of LDO regulator that have very low internal power consume and can maintain system stability with any load capacitor. This thesis also gives a thorough analysis to the technology of the LDO frequency compensation.This thesis will firstly provide a brief review on some basic knowledge and basic indicators of LDO. And then aimed at the the consumption and the speed consideration of the typical PMOS LDO model, a kind of improved system structure is put forwarded. On these grounds, the concrete circuit realization of the new system is discussed, which includes the design of each main function mold pieces. Then the whole LDO simulation result and analysis is given. And then the small signal model of LDO system and the difficulty existed in the traditional frequency compensation of LDO is analyzed from the angle of frequency-domain. Next two kinds of LDO frequency compensation improvement method is introduced, one is a compensation that is depended out of load capacitor; and the other one is the repair project under the different load current. Finally, the concrete circuit of these compensation method and it's simulation results is given.This LDO is designed on the basis of 0.6μm BiCMOS process, and its performance has been verified by Candence simulation. The minimal dropout voltage is 500 mV, maximum output current is 100 mA and the quiescent current is 50μA. Properties as liner regulation of 0.29mV/V and load regulation of 0.33mV/mA are achieved. The overall simulation results shows that better performance of LDO have been realized fully.
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