A Capacitor-less Low Drop out Voltage Regulator

Low dropout voltage regulators (LDO) use a large external capacitor, in the range of few micro-farads. These external capacitors occupy valuable board space, increase the IC pin count and prohibit System-On-Chip (SoC) solutions. The large external capacitor is replaced with a reasonable 1nF internal capacitor. The capacitor-less LDO is designed for an output voltage of 1.4V for a given supply voltage 2.2V using Cadence tool, UMC180 PDK in 0.18µm CMOS technology. The capacitor-less LDO responds within 80ns for a load current change of 0 – 5mA consuming 300uA of ground current The Line and Load regulations achieved are 0.3mV and 0.22 mV respectively. The observed overshoot and undershoot voltages are less than 50mV in all process corners. The fast transient loop used has improved line regulation, load regulation and transient response.