Design of differential circuit for LSI N-threshold comparator

The static mode of the analog element of an N-threshold comparator (differential comparison circuit) is analyzed in order to find the relationship between the parameters that determine the static accuracy of the comparator and the number N and spacing of its threshold levels. Analysis of the differential circuit makes it possible to estimate the maximum number of threshold levels of the comparator and the word length of the analog-digital converter. The step of the threshold levels is at least 120 mV; therefore, the number N is limited by the acceptable dynamic range of the signal at the input to the comparator of the large scale integration analog-digital converter. Consequently, N sub max = (5V/120mV)-1 approximately 42. if the quantity is n , 6, two or more comparators with the maximum number of thresholds can be employed in the low order bits; however, coding elements are required in this case. A similar treatment can be employed if the restrictions on the number N are determined by the acceptable value of U sub o(N) rather than the dynamic range.