DESCRIPTION
These IC’s are composed of an independent 2 channel multiplexer with common SELECT and PIN CONNECTION AND IEC LOGIC SYMBOLS April 1997 1/10 74ACT257 INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION
PIN No 1 2, 5, 14, 11 3, 6, 13, 10 4, 7, 12, 9 15 8 16 SYMBOL SELECT 1A to 4A 1B to 4B 1Y to 4Y OE GND VCC NAME AND F UNCTIO N Common Data Select Input Data Input From Source A Data Inputs from Source B 3 State Multiplexer Outputs 3 State Output Enable Inputs (Active LOW) Ground (0V) Positive Supply Voltage TRUTH TABLE INPUT S OE H L L L L X = DON’T CARE Z = HIGH IMPEDANCE OUT PUT S A X L H X X B X X X L H Y Z L H L H SELECT X L L H H LOGIC DIAGRAMS This logic diagram has not be used to estimate propagation delays 2/10 74ACT257 ABSOLUTE MAXIMUM RATINGS
Symbol VCC VI VO IIK IOK IO Tstg TL Supply Voltage DC Input Voltage DC Output Voltage DC Input Diode Current DC Output Diode Current DC Output Current Storage Temperature Lead Temperature (10 sec) Parameter Value -0.5 to +7 -0.5...
STMicroelectronics
