A Novel High Performance Standard-Cell Based ULV OTA Exploiting an Improved Basic Amplifier

In this paper we introduce an improved standard-cell-based voltage amplifier cell with low output resistance. The proposed amplifier cell exhibits a voltage gain whose value can be accurately set by the number of paralleled inverters, and its output static voltage is well controlled through a replica bias approach. A three-stage fully synthesizable OTA architecture exploiting the improved voltage amplifier is also proposed. The OTA has been designed referring to the standard-cell library of a 180nm CMOS technology with a supply voltage of 0.3V and a nominal power consumption of only 6.63 nW, and exhibits a dc-gain of 73.5 dB with a gain-bandwidth-product of 9.63 kHz. A comparison against the state of the art of ultra-low-voltage OTAs has shown that the proposed amplifier exhibits the best value of the small signal figures of merit.