A Fast Transient Response Low Drop-Out Voltage Regulator

A fast transient response low drop out voltage regulator (LDO) is presented. The requirement of fast transient response is completely application specific and is governed by the loading conditions. If load current changes too quicker, then a fast transient response is a definite requirement. The LDO is implemented in 0.18um generic CMOS technology; it generates fixed 1.6V from a 3.6V supply which on discharging goes to 1.9V. The buffer stage used is wide band OTA capable of providing rail-to-rail swing and full current to charge and discharge the large driver transistor capacitance, enabling fast slewing. Simulation result shows that the proposed circuit provides full load transient response of less than 44ns settling time and less than 30mV undershoot.