Ultra low voltage, high performance operational transconductance amplifier and its application in a tunable Gm-C filter

This paper presents an ultra low voltage, high performance Operational Transconductance Amplifier (OTA) and its application to implement a tunable Gm-C filter. The proposed OTA uses a 0.5V single supply and consumes 60@mw. Employing special CMFF and CMFB circuits has improved CMRR to 138dB in DC. Using bulk driven input stage results in higher linearity such that by applying a 500mv"p"-"p sine wave input signal at 2MHz frequency in unity gain closed loop configuration, third harmonic distortion for output voltage is -46dB and becomes -42.4dB in open loop state for 820mv"p"-"p output voltage at 2MHz. DC gain of the OTA is 47dB and its unity gain bandwidth is 17.8MHz with 20pF capacitance load due to both deliberately optimized design and special frequency compensation technique. The OTA has been used to realize a wide tunable Gm-C low-pass filter whose cutoff frequency is tunable from 1.4 to 6MHz. Proposed OTA and filter have been simulated in 0.18@mm TSMC CMOS technology with Hspice. Monte Carlo and temperature dependent simulation results are included to forecast the mismatch and temperature effects after fabrication process.

[1]  Edgar Sanchez-Sinencio,et al.  INVITED PAPER Special Section on Analog Circuits and Related Topics Low Voltage Analog Circuit Design Techniques: A Tutorial , 2000 .

[2]  Ko-chi Kuo,et al.  A linear MOS transconductor using source degeneration and adaptive biasing , 2001 .

[3]  Tsung-Hsien Lin,et al.  A 0.8-V 0.25-mW Current-Mirror OTA With 160-MHz GBW in 0.18-$\mu{\hbox {m}}$ CMOS , 2007, IEEE Transactions on Circuits and Systems II: Express Briefs.

[4]  Farzan Rezaei,et al.  A Highly Linear Operational Transconductance Amplifier (OTA) with High Common Mode Rejection Ratio , 2010, 2010 International Conference on Signal Acquisition and Processing.

[5]  Robson L. Moreno,et al.  An Ultra-Low-Voltage Ultra-Low-Power CMOS Miller OTA With Rail-to-Rail Input/Output Swing , 2007, IEEE Transactions on Circuits and Systems II: Express Briefs.

[6]  Sudhanshu Shekhar Jamuar,et al.  Low voltage analog circuit design techniques , 2002 .

[7]  Piet Wambacq,et al.  Distortion analysis of analog integrated circuits , 1998 .

[8]  Edgar Sánchez-Sinencio,et al.  Frequency-dependent harmonic-distortion analysis of a linearized cross-coupled CMOS OTA and its application to OTA-C filters , 2006, IEEE Transactions on Circuits and Systems I: Regular Papers.

[9]  Xuguang Zhang,et al.  A Novel CMOS OTA Based on Body-Driven MOSFETs and its Applications in OTA-C Filters , 2007, IEEE Transactions on Circuits and Systems I: Regular Papers.

[10]  A.J. Lopez-Martin,et al.  Very low-voltage analog signal processing based on quasi-floating gate transistors , 2004, IEEE Journal of Solid-State Circuits.

[11]  Farzan Rezaei,et al.  Ultra low-voltage, rail-to-rail input/output stage Operational Transconductance Amplifier (OTA) with high linearity and its application in a Gm-C filter , 2010, 2010 11th International Symposium on Quality Electronic Design (ISQED).

[12]  P. Kinget,et al.  0.5-V analog circuit techniques and their application in OTA and filter design , 2005, IEEE Journal of Solid-State Circuits.