Low Power N-Way Analog Multiplexer
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
The following circuit will perform the multiplexing function of N analog data inputs (way 1,... way N) to an analog output under the control of n control bits (N = 2n). Only a few transistors are used in this multiplexer. Each of them has a specific function which may be analyzed as follows: Transistor 01 forms a common current source for both logic and analog portions of the circuit. Transistors 11...; 21...; 31, 32, 33, 34 form the differential pairs of stage n; ..., stage 2; stage 1, respectively. All differential pairs are standard current switch logic. Transistors 41, 42; 43, 44; 45, 46; ...; 47, 48 are respectively the input stages of way 1, way 2, way 3... way N. Transistor 02 is the current source for the output stage only.