This part is a kind of semiconductor called 74688.

Function of this product has 8-Bit Magnitude Comparator.

Manufacturers : National Semiconductor

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Some of the text within the PDF file :

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 [ ... ]

74688 PDF Datasheet Download