X74_157
Quadruple 2-to-1 Multiplexer with Common Select and Active-Low Enable
XC3000
  | XC4000E
  | XC4000X
  | XC5200
  | XC9000
  | Spartan
  | SpartanXL
  | Virtex
  | 
Macro
  | Macro
  | Macro
  | Macro
  | Macro
  | Macro
  | Macro
  | N/A
  | 

When the active-Low enable input (G) of the X74_157 multiplexer is Low, a 4-bit word is selected from one of two sources (A3 - A0 or B3 - B0) under the control of the select input (S) and is reflected on the four outputs (Y4 - Y1). When S is Low, the outputs reflect A3 - A0; when S is High, the outputs reflect B3 - B0. When G is High, the outputs are Low.
Inputs
  | Outputs
  | 
G
  | S
  | B
  | A
  | Y
  | 
1
  | X
  | X
  | X
  | 0
  | 
0
  | 1
  | 1
  | X
  | 1
  | 
0
  | 1
  | 0
  | X
  | 0
  | 
0
  | 0
  | X
  | 1
  | 1
  | 
0
  | 0
  | X
  | 0
  | 0
  | 
