Automated design of switched-current filters

This paper describes the automated design and synthesis of switched-current (SI) filters using SCADS, a flexible CAD system integrated in a major VLSI design suite. With this system, the nonspecialist can produce high performance analog filters suitable for mixed signal CMOS IC's fabricated using only standard digital processes. To achieve high levels of performance on silicon, filter designs are realized using an enhanced differential circuit technique (S/sup 2/I) in its integrators and sample-and-hold cells. The design system is described in terms of the embedded circuits, its integrated tool set, the filter design flow and the engineering procedures for ensuring reliable circuit operation. Examples of high performance video frequency filters are presented, each generated automatically by SCADS within one day. Fabricated in a 0.8 /spl mu/m standard CMOS process, they demonstrate state-of-the-art performance.

[1]  J. I. Sewell,et al.  General analysis of large linear switched capacitor networks , 1988 .

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

[3]  John B. Hughes,et al.  S/sup 2/I: a switched-current technique for high performance , 1993 .

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

[5]  John B. Hughes,et al.  Switched-Current Circuit Design Techniques , 1993 .

[6]  Li Ping,et al.  Analog integrated filter compilation , 1993 .

[7]  John B. Hughes,et al.  Switched-current cells for design automation , 1995, Proceedings of ISCAS'95 - International Symposium on Circuits and Systems.

[8]  Terri S. Fiez,et al.  Accurate SI filters using RGC integrators , 1994 .

[9]  John B. Hughes,et al.  New switched-current integrator , 1990 .

[10]  Yannis Tsividis,et al.  Sampled-current circuits , 1989, IEEE International Symposium on Circuits and Systems,.

[11]  Kenneth W. Moulding,et al.  An 8 MHz, 80 Ms/s switched-current filter , 1994, Proceedings of IEEE International Solid-State Circuits Conference - ISSCC '94.

[12]  John I. Sewell,et al.  Efficient noise analysis methods for large non-ideal SC and SI circuits , 1994, Proceedings of IEEE International Symposium on Circuits and Systems - ISCAS '94.

[13]  Christofer Toumazou,et al.  A 5th order bilinear elliptic switched-current filter , 1993, Proceedings of IEEE Custom Integrated Circuits Conference - CICC '93.

[14]  David J. Allstot,et al.  Low-voltage fully-differential CMOS switched-current filters , 1993 .

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

[16]  John B. Hughes,et al.  Switched-current signal processing for video frequencies and beyond , 1993 .

[17]  John B. Hughes,et al.  A switched-current double sampling bilinear z-transform filter technique , 1994, Proceedings of IEEE International Symposium on Circuits and Systems - ISCAS '94.

[18]  J Richardson,et al.  An Integrated Design and Synthesis System for High Performance Switched-Current Analogue Filters , 1995, ESSCIRC '95: Twenty-first European Solid-State Circuits Conference.