Abstract: A full on-chip CMOS low-dropout (LDO) voltage regulator with high PSR is presented. Instead of relying on the zero generated by the load capacitor and its equivalent series resistance, the proposed LDO generates a zero by voltage-controlled current sources for stability. The compensating capacitor for the proposed scheme is only 0.18 pF, which is much smaller than the capacitor of the conventional compensation scheme. The full on-chip LDO was fabricated in commercial 0.35 μ m CMOS technology. The active chip area of the LDO (including the bandgap voltage reference) is 400 × 270 μ m². Experimental results show that the PSR of the LDO is –58.7 dB at a frequency of 10 Hz and –20 dB at a frequency of 1 MHz. The proposed LDO is capable of sourcing an output current up to 50 mA.

Key words: voltage regulator, full on-chip, high PSR, VCCS, LDO