Low-voltage low-power amplifiers

Low-voltage and low-power amplifiers are strongly limited in dynamic range (DR) and bandwidth (B). The maximum dynamic-range/supply-power ratio is restricted to DR/sub max//P/sub sup/ = /spl pi//16 kTBe by thermal noise in resistors. To obtain this maximum value, several rail-to-rail (R-R) input stages and R-R output stages biased in class-AB are designed. The maximum bandwidth/supply-power ratio is restricted to B/sub 0max//P/sub sup/ = 3/C/sub L/V/sub sup/, and B/sub 0max//P/sub sup/ = 1/120I/sup 1/2//sub D/C/sub L/V/sub sup/, respectively, for bipolar and CMOS transistors. To obtain this maximum value at a sufficient amount of low-frequency gain, several compensation structures are designed, such as parallel, Miller, and multipath nested Miller compensation.<>