A sub-threshold ultra-low power low-dropout regulator

In this paper, a wide range low dropout (LDO) with low current consumption is presented. The circuitry is constructed by a sub-threshold voltage error amplifier (EA). The transistors of EA operate in the sub-threshold region, which allows a remarkable reduction in the minimum supply voltage and current consumption. In the condition of input voltage 2 ∼ 5V, output voltage 1.8 V, load capacitor 4.7μΕ, and load current 100 mA, the current consumption of the LDO is 3.6 μΑ. The output LDO can be adjusted from 1.6 V to 2.15 V by the 4 bit trimming step of 50 mV. The propose LDO is implement in CMOS 110 nm technology using UMC's process with the active die size of 222 μm × 184 μm.