Title :
A new MOSFET-C universal filter structure for VLSI
Author :
Ismail, Mohammed ; Smith, Shirley V. ; Beale, Richard G.
Author_Institution :
Dept. of Electr. Eng., Nebraska Univ., Lincoln, NE, USA
Abstract :
A continuous-time all-MOS universal filter structure is proposed. The structure is based on the MOSFET-C design approach. It achieves complete MOS nonlinearity cancellation and does not require the use of fully balanced op-amps. General topological requirements are established that are necessary for the conversion of active-RC prototypes to MOSFET-C counterparts, such that MOS nonlinearity cancellation is achieved. Accordingly, a universal active-RC prototype filter structure, which meets the necessary requirements, is presented and its MOSFET-C version is developed. Nonideal effects that may degrade the performance at high frequency are discussed and ways for improvement are proposed. Results obtained from a test chip have verified the viability of the proposed structures. The chip is an implementation of a MOSFET-C universal filter in a 3.5- mu m CMOS process. The filter is successfully tuned over a wide range of pole frequencies (0 to 100 kHz) using op-amps with a measured gain bandwidth of only 1.2 MHz.<>
Keywords :
CMOS integrated circuits; VLSI; active filters; 0 to 100 kHz; 1.3 MHz; 3.5 micron; CMOS process; MOS nonlinearity cancellation; MOSFET-C universal filter structure; VLSI; active-RC prototype filter; active-RC prototypes; fully balanced op-amps; gain bandwidth; pole frequencies; CMOS process; Degradation; Filters; Frequency measurement; Gain measurement; MOSFET circuits; Operational amplifiers; Prototypes; Testing; Very large scale integration;
Journal_Title :
Solid-State Circuits, IEEE Journal of
