MM74HCT688

MM54HCT688 MM74HCT688 8-Bit Magnitude Comparator (Equality Detector) February 1988 MM54HCT688 MM74HCT688 8-Bit Magnitude Comparator (Equality Detector) General Description This equality detector utilizes advanced silicon-gate CMOS technology to compare bit for bit two 8-bit words and indicate whether or not they are equal The PeQ output indicates equality when it is low A single active low enable is provided to facilitate cascading of several packages and enable comparison of words greater than 8 bits This device is useful in memory block decoding applications where memory block enable signals must be generated from computer address information The comparator combines the low power consumption of CMOS but inputs are compatible with TTL logic levels and the output can drive 10 low power Schottky equivalent loads MM54HCT MM74HCT devices are intended to interface between TTL and NMOS components and standard CMOS devices These parts are also plug in replacements for LSTTL devices and can be used to reduce power consumption in existing designs All inputs are protected from damage due to static discharge by diodes to VCC and ground Features Y TTL input compatible Y Typical propagation delay 20 ns Y Low quiescent current 80 mA maximum (74HCT Series) Y Large output current 4 mA Y Same as HCT521 Logic Diagrams C1995 National Semiconductor Corporation TL F 5371 TL F 5371 – 2 RRD-B30M105 Printed in U S A Absolute Maximum Ratings (Notes 1 2) If Military Aerospace specified devic...