Signetics Utilogic DTL
Signetics Utilogic II DTL ICs are Diode-Transistor-Logic. SP prefix series are good for +0C to +75'C wheras LU prefixes are good for 10C to 55C. Sometimes coming in plastic carriers around a normal N package IC to aid in lead protection and ease of handling/insertion probing and testing. UTILOGIC is a logic family developed by Signetics for application in commercial, industrial and ground support equipment where favoured performance includes high capacitive drive capability and high noise margins.