HEF4042B

The HEF4042B is a 4-bit latch with four data inputs (D₀ to D₃), four buffered latch outputs (O0 to O3), four bufferedcomplementary latch outputs (O₀ to O₃) and two common enable inputs (E₀ and E₁). Information of HEF4042B on D₀ to D₃ is transferred to O₀ to O₃ while both E0 and E1 are in the same state, either HIGH or LOW. O0 to O3 follow D0 to D3 as long as both E0 and E1 remain in the same state. When E0 and E1 are different, D₀ to D₃ do not affect O₀ to O₃ and the information in the latch is stored.

O₀ to O₃ are always the complement of O0 to O3. The exclusive-OR input structure allows the choice of either polarity for E0 and E1. With one enable input HIGH, the other enable input is active HIGH; with one enable input LOW, the other enable input is active LOW.