A Common Drain Operational Amplifier Using Positive Feedback Integrated by Metal-Oxide TFTs

作者：Mei, Xiang-Lin; Chen, Zhuo-Jia; Xu, Wen-Xing; Zhou, Lei; Wu, Wei-Jing^*; Zou, Jian-Hua; Xu, Miao; Wang, Lei; Liu, Yu-Rong; Peng, Jun-Biao

来源：IEEE Journal of the Electron Devices Society, 2021, 9: 342-347.

DOI：10.1109/JEDS.2021.3060954

• Cross-coupled
• common-drain
• indium-zinc-oxide (IZO) thin-film transistors (TFTs)
• positive feedback
• operational amplifier (OPAMP)

This paper presents a common-drain-based operational amplifier (OPAMP) fabricated by mono n-type indium-zinc-oxide (IZO) thin-film transistors (TFTs). Positive feedback technology is employed to the load TFTs by cross-coupled connection in order to boost the voltage gain of the common-drain differential pair. The OPAMP exhibits an open-loop voltage gain (A(v)) of 27 dB over a -3 dB bandwidth (BW) of 8.4 kHz at a DC supply voltage of 10 V. The measured unity-gain frequency (UGF), phase margin (PM) and DC power consumption are 119.4 kHz, 36 degrees and 0.96 mW, respectively. Moreover, the chip area of the proposed OPAMP is as small as 0.37 mm x 3 mm since this concise topology needs only 10 TFTs.