A low-dropout regulator (LDO) with fast-transient response speed is presented by utilizing the proposed transient response enhancement (TRE) circuit,which doesn't bring the quiescent current increase.The proposed LDO has been fabricated in a 0.5 μm standard CMOS process,and the die area is 0.49mm².The proposed LDO dissipates 23 μA quiescent current at no-load condition and is able to deliver up to 200mA load current.With a 1 μF output capacitor,the maximum transient output-voltage variation is within 3.5% of the output voltage with load step changes of 200mA/100ns.