MC74ACT257

( DataSheet : www.DataSheet4U.com ) MC74AC257 MC74ACT257 Quad 2ĆInput Multiplexer with 3ĆState Outputs The MC74AC257/74ACT257 is a quad 2-input multiplexer with 3-state outputs. Four bits of data from two sources can be selected using a Common Data Select input. The four outputs present the selected data in true (noninverted) form. The outputs may be switched to a high impedance state by placing a logic HIGH on the common Output Enable (OE) input, allowing the outputs to interface directly with bus-oriented systems. Multiplexer Expansion by Tying Outputs Together Noninverting 3-State Outputs Outputs Source/Sink 24 mA ′ACT257 Has TTL Compatible Inputs VCC 16 OE 15 I0c 14 I1c 13 Zc 12 I0d 11 I1d 10 Zd 9 QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS N SUFFIX CASE 648-08 PLASTIC PIN NAMES S OE I0a–I0d I1a–I1d Za–Zd Common Data Select Input 3-State Output Enable Input Data Inputs from Source 0 Data Inputs from Source 1 3-State Multiplexer Outputs D SUFFIX CASE 751B-05 PLASTIC 1 S 2 I0a 3 I1a 4 Za 5 I0b 6 I1b 7 Zb 8 GND TRUTH TABLE Output Enable OE H L L L L H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial Z = High Impedance LOGIC SYMBOL Select Input S X H H L L Data Inputs I0 X X X L H I1 X L H X X Outputs Z Z L H L H S Za Zb Zc Zd OE I0a I1a I0b I1b I0c I1c I0d I1d www.DataSheet4U.com www.DataSheet4U.com FACT DATA 5-1 MC74AC257 MC74ACT257 FUNCTIONAL DESCRIPTION The MC74AC257/74ACT257 is a quad 2-input multiplexer with 3-state outputs. It selec...