MC74LCX258 Low-Voltage CMOS Quad 2-Input Multiplexer With 5 VTolerant Inputs and Outputs (3State, Inverting) MC74LCX258 A3 B3 Y3 A2 B2 V OE Y2 CC PIN NAMES 16 15 14 13 12 11 10 9 Pins Function An Source 0 Data Inputs Bn Source B Data Inputs OE Enable Input S Select Input 1 2 3456 7 8 Yn Outputs A0 B0 B1 S Y0 A1 Y1 GND Figure 1. Pinout: 16Lead Plastic Package (Top View) TRUTH TABLE Inputs Outputs Output Enable Select Y0 Y3 H X Z L L A0A3 L H B0B3 X = Dont Care A0A3, B0B3 = The levels of the respective Data Word Inputs PIN DESCRIPTIONS INPUTS OUTPUTS A0A3 (Pins 2, 5, 11, 14) Y0 Y3 (Pins 4, 7, 9, 12) Nibble A inputs. The data present on these pins is Data outputs. The selected input nibble is presented at transferred to the outputs when the Select input is at a low these outputs when the Output Enable input is at a low level. level and the Output Enable input is at a low level. The data The data present on these pins is in its inverted form for the is presented to the outputs in inverted form for the LCX258. LCX258. For the Output Enable input at a high level, the outputs are at a high level for the LCX258. B0 B3 (Pins 3, 6, 10, 13) Nibble B inputs. The data present on these pins is Select (Pin 1) transferred to the outputs when the Select input is at a high Nibble select. This input determines the data word to be level and the Output Enable input is at a low level. The data transferred to the outputs. A low level on this input selects is presented to the outputs in inverted form for the LCX258. the A inputs and a high level selects the B inputs. CONTROL INPUTS Output Enable (Pin 15) Output Enable input. A low level on this input allows the selected data to be presented at the outputs. A high level on this input sets all of the outputs to 3state off.