A large-signal very low-distortion transconductor for high-frequency continuous-time filters

A high-frequency large-signal very low-distortion voltage-to-current transducer is presented. The total harmonic distortion (THD), for supply voltages of only +or-2.5 V, is smaller than 0.1% for fully differential input signals up to 2.4 V peak to peak (V/sub pp/). The dynamic range is on the order of 89 dB with the transconductor noise integrated over a bandwidth of 1 MHz. Moreover, this structure presents low sensitivity to transistor mismatches. An operational transconductance amplifier (OTA), based on this transconductor, has been used in an adjustable quality factor 1.8-MHz biquadratic continuous-time filter. The quality factor Q is controlled, from 2 to 50, with a novel current-source configuration. Both the OTA and the filter have been fabricated in a CMOS 3- mu m n-well process. >

[1]  R. Schaumann,et al.  Design of a 4-MHz analog integrated CMOS transconductance-C bandpass filter , 1988 .

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

[3]  M. Banu,et al.  An elliptic continuous-time CMOS filter with on-chip automatic tuning , 1985, IEEE Journal of Solid-State Circuits.

[4]  Y. Tsividis,et al.  A 5 V 7th-order elliptic analog filter for digital video applications , 1990, 1990 37th IEEE International Conference on Solid-State Circuits.

[5]  E. Sanchez-Sinencio,et al.  Active filter design using operational transconductance amplifiers: A tutorial , 1985, IEEE Circuits and Devices Magazine.

[6]  Yannis Tsividis,et al.  Continuous-time MOSFET-C filters in VLSI , 1986 .

[7]  J. Hanson,et al.  CMOS voltage to current transducers , 1985 .

[8]  Steven L. Garverick.  Large signal linearity of scaled MOS transistors , 1986 .

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

[10]  A. Abidi,et al.  A 12.5 MHz CMOS continuous time bandpass filter , 1989, IEEE International Solid-State Circuits Conference, 1989 ISSCC. Digest of Technical Papers.

[11]  Mohammed S. Ghausi,et al.  Very high-Q insensitive active RC networks , 1970 .

[12]  P. R. Gray,et al.  High-frequency CMOS continuous-time filters , 1984 .

[13]  P.M. Van Peteghem,et al.  A very-linear CMOS transconductance stage for OTA-C filters , 1989, 1989 Proceedings of the IEEE Custom Integrated Circuits Conference.

[14]  K. Bult,et al.  A class of analog CMOS circuits based on the square-law characteristic of an MOS transistor in saturation , 1987 .

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

[16]  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.