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MM54HC149/MM74HC1498 Line to 8 Line Priority EncoderGeneral DescripTIonThis priority encoder uTIlizes advanced silicon-gate CMOStechnology. It has the high noise immunity and low powerconsumpTIon typical of CMOS circuits, as well as the speedsand output drive similar to LS-TTL.This priority encoder accepts 8 input request lines, RI7±RI0,and outputs 8 lines, RO7±RO0. Only one request outputcan be low at a TIme. The output that is low is dependent onthe highest priority request that is low. The order of priorityis RI7 highest and RI0 lowest. Also provided is and enableinput, RQE, which when high forces all outputs high. A requestoutput is also provided, RQP, which goes low whenany RIn is active.All inputs to this device are protected from damage due toelectrostatic discharge by diodes to VCC and ground.FeaturesY Propagation delay: 15 ns typicalY Wide power supply range: 2±6VY Low quiescent current: 80 mA max (74HC Series)Y Wide input noise immunity
