Abstract
Techniques are developed for realizing CM OS transconductance amplifiers with increased transconductance adjustment ranges. In transconductor-based electronic systems, the transconductance adjustment is useful in overcoming integrated circuit process variations and in implementing systems with program m able specifications. Linearity of the transfer characteristic is also highly desirable; however the adjustment of previously-reported transconductors via adjustment of a tail current in a differential-pair-based input stage typically involves severe linearity degradation. The techniques presented in this work are based on the use of program m able current mirrors as a means of transconductance adjustment; furthermore, current mirrors are presented which actually perform the desired linearization of the currents generated by a simple differential pair input stage. This leads to fairly simply transconductor circuits which largely avoid the adjustment/linearity tradeoffs inherent in many previous designs. Experimental results verify the extended adjustment/linearization schemes. A detailed analysis of mismatch effects is included which suggests methods by which these undesirable effects may be reduced.
Adams, William John (1991). CMOS operational transconductance amplifiers with extended transconductance adjustment ranges. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -1274326.