Wide-Range Current-Controlled Floating Resistor for CMOS Technology

This paper presents a current-controllable CMOS floating resistor (CCFR) possessing a number of interesting features. Its functioning has been verified by performing simulations on Cadence VIRTUOSO software at 0.18 & mu;m CMOS technology. The proposed circuit operates with a supply voltage of & PLUSMN; 0.6 V and the value of the realised resistance can be varied from 13k & OHM; to 1.3G & OHM; (five decades), when the bias current (I-o) is varied from 10pA to 1 & mu;A, with a maximum linearity error of less than 4%. The circuit operates well up to a frequency of 50 MHz and consumes a power of only 26 & mu;W at the maximum bias current of 1 & mu;A. Furthermore, post-layout simulations and corner analysis are carried out to evaluate its resilience in the presence of manufacturing non-idealities. A Sallen-Key high-pass filter with electronically-controllable cut-off frequency has been implemented by replacing the two resistors of the filter circuit by the proposed CCFRs and the workability of this arrangement has also been confirmed by simulations.