A novel CMOS operational transconductance amplifier based on a mobility compensation technique

This brief describes a new linear operational transconductance amplifier (OTA) and its application to a ninth-order Bessel filter. To improve the linearity of the OTA, we employ a mobility compensation circuit which combines the transistors operating in the triode and the subthreshold regions. The proposed technique enhances the linearity of the transconductance without loss of the input swing range. The proposed OTA shows /spl plusmn/0.5% Gm variation and the total harmonic distortion of less than - 60-dB over the input range of /spl plusmn/0.8-V. The ninth-order Bessel filter employing the proposed OTA has been implemented in a 0.35-/spl mu/m n-well CMOS process under 3.3-V supply voltage. It shows the cutoff frequency of 8 MHz and the power consumption of 65 mW.

[1]  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.

[2]  Yong-Hwan Kim,et al.  A CMOS 4/spl times/ speed DVD read channel IC , 1998 .

[3]  P. E. Allen,et al.  Low-voltage CMOS transconductance cell based on parallel operation of triode and saturation transconductors , 1994 .

[4]  Eitake Ibaragi,et al.  A CMOS Analog Multiplier Free from Mobility Reduction and Body Effect , 1999 .

[5]  Fuji Yang,et al.  A low-distortion BiCMOS seventh-order Bessel filter operating at 2.5 V supply , 1996 .

[6]  Y. Tsividis.  Operation and modeling of the MOS transistor , 1987 .

[7]  S. L. Wong,et al.  Novel drain-biased transconductance building blocks for continuous-time filter applications , 1989 .

[8]  Eric A. M. Klumperink,et al.  Low-voltage CMOS transductance cell based on parallel operation of triode and saturation transconductors , 1994 .

[9]  Kuen-Jong Lee,et al.  A current-mode testable design of operational transconductance amplifier-capacitor filters , 1999 .

[10]  Edgar Sanchez-Sinencio,et al.  A fully balanced pseudo-differential OTA with common-mode feedforward and inherent common-mode feedback detector , 2003, IEEE J. Solid State Circuits.

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

[12]  N. D. Arora,et al.  MOSFET Models for VLSI Circuit Simulation: Theory and Practice , 1993 .

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

[14]  P. R. Gray,et al.  A 20-MHz sixth-order BiCMOS parasitic-insensitive continuous-time filter and second-order equalizer optimized for disk-drive read channels , 1993 .

[15]  Edgar Sanchez-Sinencio,et al.  CMOS transconductance amplifiers, architectures and active filters: a tutorial , 2000 .

[16]  C. Toumazou,et al.  A 290 nW, weak inversion, Gm-C biquad , 2002, 2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353).