A 1.8 V 8.62 µW Inverter-based Gain-boosted OTA with 109.3 dB dc Gain for SC Circuits

ABSTRACT

This paper presents a low-power inverter-based gain-boosted operational transconductance amplifier (OTA) for switched capacitor (SC) circuits operating at higher supply voltage (>1 V). The proposed OTA is implemented using UMC 180 nm CMOS technology with a supply voltage of 1.8 V and it offers a high dc gain with a unity gain bandwidth (UGB) suitable for audio applications. All the transistors of the proposed OTA are operated in sub-threshold region to minimize the power consumption. Gain-boosting technique is employed to achieve a higher dc gain. The post-layout simulations demonstrate the robust performance of the proposed OTA, which delivers a high dc gain of 109.3 dB and a UGB of 5.29 MHz at 81° phase margin (PM) with a capacitive load of 2.5 pF for a typical process corner at room temperature (27°C). The proposed OTA draws a quiescent current ($I_Q$) of 4.79 µA, resulting in a power consumption of 8.62 µW.

KEYWORDS:

• Gain-boosting
• High gain
• Inverter-based
• Low power
• OTA
• Switched capacitor

Acknowledgments

The authors would like to thank MeitY, Government of India, for providing the EDA tool through SMDP-VLSI project.

Additional information

Notes on contributors

Yajunath Kaliyath

Yajunath Kaliyath received his B.Tech. degree in Electronics and Communication Engineering from Lakireddy Bali Reddy College of Engg., Mylavaram, India (affiliated to JNTUK, Kakinada) in 2009 and M. Tech. degree in VLSI Design from NITK, Surathkal, India in 2012. Presently, he is working towards the Ph.D. degree in the Department of Electronics and Communication Engineering at NITK, Surathkal, India. His research interests include low power analog IC design.

Tonse Laxminidhi

Tonse Laxminidhi received his B.E. degree in Electrical Engineering from NMAM Institute of Technology, Nitte, India (affiliated to Mangalore University) in 1996, M.Tech. degree from KREC, Surathkal, India (affiliated to Mangalore University) in 1998 and PhD degree from Indian Institute of Technology, Madras, India in 2008. He joined the Department of Electronics and Communication Engineering, NITK Surathkal as a faculty in 2000 and currently, he is an associate professor in the department. His research interests include analog and mixed signal design and power management circuits. Email: [email protected]