High-gain, bulk-driven operational amplifiers for system-on-chip applications

摘要

An ultra-low voltage rail-to-rail operational transconductance amplifier (OTA) is based on a standard digital 0.18 μm CMOS process. Techniques for designing a 0.8 volt fully differential OTA include bias and reference current generator circuits. To achieve rail-to-rail operation, complementary input differential pairs are used, where the bulk-driven technique is applied to reduce the threshold limitation of the MOSFET transistors. The OTA gain is increased by using auxiliary gain boosting amplifiers.