A low-quiescent-current fast-response current-feedback shunt regulator is presented in this paper. The structure of shunt regulator topology is found superior to series regulator topology in terms of radiation tolerance. By utilizing the shunt regulator architecture suppress stray effect of power supply. Current conveyor (CCII) based shunt regulator provides current feedback for fast response. A shunt regulator with a CCII based driving the regulation field-effect transistor is presented. The shunt regulator can also be stable even without the output capacitor. The maximum output current of the shunt regulator is 180 mA at an output of 1.8 V. When power supply 200 mA and output voltage 1.8 V, its quiescent current is only 315 nA and is able to recover within 1 mus even under the worst case scenario. The prototype of the shunt regulator is fabricated with TSMC 0.35-mum CMOS processes. The chip area (include I/O pad) is only 658 mum times 554 mum.