HEF4556B

The HEF4556B is a dual 1-of-4 decoder/demultiplexer. Each has two address inputs (A₀ and A₁), an active LOW enable input (E) and four mutually exclusive outputs which are active LOW (O₀ to O₃). When used as a decoder, E when HIGH, forces O₀ to O₃ HIGH. When used as a demultiplexer, the appropriate output is selected by the information on A0 and A1 with E as data input. All unselected outputs of HEF4556B are HIGH.