CMOS continuous-time current-mode filters for high-frequency applications

Design considerations for high-frequency CMOS continuous-time current-mode filters are presented. The basic building block is a differential current integrator with its gain constant set by a small-signal transconductance and a gate capacitance. A prototype fifth-order low-pass ladder filter implemented in a standard digital 2 mu m n-well CMOS process achieved a -3 dB cutoff frequency (f/sub 0/) of 42 MHz; f/sub 0/ was tunable from 24 to 42 MHZ by varying a reference bias current from 50 to 150 mu A. Using a single 5 V power supply with a nominal reference current of 100 mu A, the five-pole filter dissipated 25.5 mW. The active filter area was 0.056 mm/sup 2//pole. With the minimum input signal defined as the input-referred noise integrated over a 40 MHz bandwidth, and the maximum input signal defined at the 1% total intermodulation distortion (TIMD) level, the measured dynamic range was 69 dB. A third-order elliptic low-pass ladder filter was also integrated in the 2 mu m n-well CMOS process to verify the implementation of finite transmission zeros. >

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

[2]  J. Schoeff,et al.  An inherently monotonic 12 bit DAC , 1979, IEEE Journal of Solid-State Circuits.

[3]  P. R. Gray,et al.  Fully integrated analog filters using bipolar-JFET technology [active fifth order Chebyshev low-pass realisation] , 1978 .

[4]  H. Blinchikoff,et al.  Filtering in the time and frequency domains , 1976 .

[5]  A. S. Sedra,et al.  The current conveyor: history and progress , 1989, IEEE International Symposium on Circuits and Systems,.

[6]  Yannis Tsividis,et al.  Design considerations for high-frequency continuous-time filters and implementation of an antialiasing filter for digital video , 1990 .

[7]  William Martin Snelgrove,et al.  A balanced 0.9- mu m CMOS transconductance-C filter tunable over the VHF range , 1992 .

[8]  D.J. Allstot,et al.  A 40 Mhz Cmos Continuous-time Current-mode Filter , 1992, 1992 Proceedings of the IEEE Custom Integrated Circuits Conference.

[9]  David J. Allstot,et al.  Switched-current circuit design issues , 1991 .

[10]  John B. Hughes,et al.  Switched-current Video Signal Processing , 1992, 1992 Proceedings of the IEEE Custom Integrated Circuits Conference.

[11]  J. Lohstroh,et al.  Devices and circuits for bipolar (V)LSI , 1981, Proceedings of the IEEE.

[12]  J. M. Khoury.  Design of a 15-MHz CMOS continuous-time filter with on-chip tuning , 1991 .

[13]  David J. Allstot,et al.  CMOS switched-current ladder filters , 1990 .

[14]  Christofer Toumazou,et al.  Current-mode analogue signal processing circuits-a review of recent developments , 1989, IEEE International Symposium on Circuits and Systems,.

[15]  S. Darlington,et al.  Synthesis of Reactance 4-Poles Which Produce Prescribed Insertion Loss Characteristics: Including Special Applications To Filter Design , 1939 .

[16]  David J. Allstot,et al.  Signal-dependent clock-feedthrough cancellation in switched-current circuits , 1991, China., 1991 International Conference on Circuits and Systems.

[17]  Jaime Ramirez-Angulo,et al.  Current-mode continuous-time filters: two design approaches , 1992 .

[18]  David J. Allstot,et al.  A continuous-time current-mode integrator , 1991 .

[19]  John B. Hughes,et al.  Switched currents-a new technique for analog sampled-data signal processing , 1989, IEEE International Symposium on Circuits and Systems,.

[20]  M.J.M. Pelgrom,et al.  Matching properties of MOS transistors , 1989 .

[21]  Bram Nauta,et al.  A CMOS transconductance-C filter technique for very high frequencies , 1992 .

[22]  R.W. Brodersen,et al.  An electrically-programmable switched capacitor filter , 1979, IEEE Journal of Solid-State Circuits.

[23]  Evert Seevinck,et al.  Current-mode techniques for high-speed VLSI circuits with application to current sense amplifier for CMOS SRAM's , 1991 .

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

[25]  Terri S. Fiez,et al.  Fully-differential CMOS current-mode circuits , 1991, Proceedings of the IEEE 1991 Custom Integrated Circuits Conference.

[26]  P. Gray,et al.  Design techniques for MOS switched capacitor ladder filters , 1978 .

[27]  Brett Wilson.  Current-mode amplifiers , 1989, IEEE International Symposium on Circuits and Systems,.