A Highly Linear Operational Transconductance Amplifier (OTA) with High Common Mode Rejection Ratio

This paper presents a highly linear Operational Transconductance Amplifier (OTA) that combines two linearization techniques, one with adaptive biasing of differential pairs and second with using of resistive source degeneration. OTA has ±0.9v power supply and consumes 456 µw. Improvement of adaptive bias circuit has enhanced the CMRR to 135dB in DC. OTA has been simulated with TSMC 0.18µm technology in Hspice. The simulated third order harmonic distortion (HD3) with applying a 600mvP-P differential input, remains below -67dB at 3MHz frequency.

[1]  Edgar Sánchez-Sinencio,et al.  Robust highly linear high-frequency CMOS OTA with IM3 below - 70 dB at 26 MHz , 2006, IEEE Transactions on Circuits and Systems I: Regular Papers.

[2]  J. Jakusz,et al.  A linear fully balanced CMOS OTA for VHF filtering applications , 1997 .

[3]  Francois Krummenacher,et al.  A 4-MHz CMOS Continuous-Time Filter with On-Chip Automatic Tuning , 1987, ESSCIRC '87: 13th European Solid-State Circuits Conference.

[4]  Terri S. Fiez,et al.  A CMOS transconductor with 80-dB SFDR up to 10 MHz , 2002 .

[5]  Il-Song Han.  A Novel Tunable Transconductance Amplifier Based on Voltage-Controlled Resistance by MOS Transistors , 2006, IEEE Transactions on Circuits and Systems II: Express Briefs.

[6]  Ashok Nedungadi,et al.  Design of linear CMOS transconductance elements , 1984 .

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

[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]  Slawomir Koziel,et al.  Design of highly linear tunable CMOS OTA for continuous-time filters , 2002 .

[10]  José Silva-Martínez,et al.  A 30-MHz Fifth-Order Elliptic Low-Pass CMOS Filter With 65-dB Spurious-Free Dynamic Range , 2007, IEEE Transactions on Circuits and Systems I: Regular Papers.

[11]  Chung-Chih Hung,et al.  A 1-V 50-MHz Pseudodifferential OTA With Compensation of the Mobility Reduction , 2007, IEEE Transactions on Circuits and Systems II: Express Briefs.

[12]  E. Sánchez-Sinencio,et al.  Nonlinear effects in pseudo differential OTAs with CMFB , 2003, IEEE Trans. Circuits Syst. II Express Briefs.

[13]  José Silva-Martínez,et al.  OTA linearity enhancement technique for high frequency applications with IM3 below -65 dB , 2004, IEEE Transactions on Circuits and Systems II: Express Briefs.

[14]  Ramón González Carvajal,et al.  Low Voltage Differential Input Stage With Improved CMRR and True Rail-to-Rail Common Mode Input Range , 2008, IEEE Transactions on Circuits and Systems II: Express Briefs.

[15]  W. Guggenbuhl,et al.  A voltage-controllable linear MOS transconductor using bias offset technique , 1990 .

[16]  E. Seevinck,et al.  A versatile CMOS linear transconductor/square-law function , 1987 .