MM54HC521/MM74HC521 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 indicates 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's output can drive 10 low power Schottky equivalent loads. This comparator is functionally and pin compatible to the 54LS688/74LS688 and the 54HC688/ 74HC688. All inputs are protected from damage due to static discharge by diodes to VCC and ground. Features Y Typical propagation delay: 20 ns Y Wide power supply range: 2±6V Y Low quiescent current: 80 mA (74 Series) Y Large output current: 4 mA (74 Series) Y Identical to 'HC688