A New High-Gain Operational Amplifier Using Transconductance-Enhancement Topology Integrated With Metal Oxide TFTs

Abstract

This paper presents an integrated operational amplifier (OPAMP) consisting of only n-type metal oxide thin-film transistors. In addition to using positive feedback in the input differential pair, a transconductance-enhancement topology is applied to improve the gain of the OPAMP. The OPAMP has a voltage gain ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$A_{v}$ </tex-math></inline-formula> ) of 29.54 dB over a 3-dB bandwidth of 9.33 kHz at a supply voltage of 15 V. The unity-gain frequency, phase margin (PM), and dc power consumption ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm{ DC}}$ </tex-math></inline-formula> ) are 180.2 kHz, 21.5° PM and 5.07 mW, respectively.