This paper proposes an input current-differencing technique in designing a capacitor-free low-dropout regulator to simultaneously achieve sleep-mode efficiency and silicon real estate saving. With no minimum output current required to be stable, the regulator could greatly improve SoC efficiency during standby, which is extremely attractive for battery powered applications. Designed in TSMC 0.18-lm CMOS technology, it regulates 1.8-1.2 V supply down to 1 V with 100 mA maximum output current and can drive up to 100 pF of load parasitic capacitance. Compared with prior arts with the same sleep-mode compatibility and similar output current range, it reduces the on-chip compensation capacitance from 21 to 4.5 pF.