A 35.2-kHz, 75.4-dB Bulk-Driven OTA Using Degenerative Current Tram Structure

This article reports on the design of a high-performance operational transconductance amplifier (OTA) based on a degenerative current translation and mirroring (DI-Tram) circuit. The DI-Tram serves as the core of a high-performance, bulk-driven (BD), voltage-to-current (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V/I</i>) converter. The proposed OTA features a current mode, indirect Miller compensation technique, which improves the stability and gain–bandwidth (GBW) product. Fabricated in a 180-nm CMOS process, the OTA consumes as low as 39.1 nW of power when operated using a supply voltage of ±0.2 V. The circuit achieves a GBW of 35.2 kHz, a dc gain of 75.4 dB, and a common-mode rejection ratio (CMRR) exceeding 117 dB while driving a capacitive load of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 20$</tex-math> </inline-formula> pF.