A Fast-Transient Low-Dropout Regulator With Load-Tracking Impedance Adjustment and Loop-Gain Boosting Technique

A low-voltage fast-transient low dropout (LDO) regulator compensated by an off-chip, low-equivalent-series-resistance (ESR), nanorange output capacitor is reported in this brief. The proposed load-tracking impedance adjustment and the loop-gain boosting technique make the proposed LDO regulator have fast response and small voltage spikes. The circuit is implemented by a commercial 0.35- μm CMOS technology. The chip area is 0.032 mm2. The supply voltage ranges from 1.5 to 3 V. The regulated voltage is 1.2 V to provide 0-100 mA. The quiescent current in the no-load condition is 26 μA. A 100-nF low-ESR capacitor is sufficient to stabilize the proposed LDO regulator. The measured voltage spike is 44.9 mV only, and the response time is less than 0.2 μs.