A 0.25-V PVT-Stabilized Bulk-Driven Fully-Differential OTA for Multi-Modal Signal Processing

In this paper, a low-power operational amplifier applied in multi-modal information processing sensors are proposed. A 0.25-V process, voltage and temperature (PVT) stabilized bulk-driven OTA using the proposed common-mode (CM) active compensation and active Q-modulation (AQM) is designed to verify proposed theory. Without changing the coarse feedback amplifier, the poles and zeros can be effectively handled in CM condition, so as to stabilize the oscillating loop, and the Q can also be modulated under differential mode (DM) to optimize the establishment effect. Proposed OTA with our technique is implemented in a 65nm CMOS technology with 0.00031 mm2 chip area and 30nW power consumption. More than 69kHz UGF, and 29V/ms SR with a 20pF load can be achieved with 65° phase margin in CM and 72° in DM.