Standard Logic 74LS Series 6-Circuit Inverter (NOT Circuit) The output is an open collector and can be used for special purposes such as wire OR/AND level conversion but it also requires pull-up resistance when used as an inverter. The 74LS04 standard output format does not replace it. Specifications: Package: DIP14; Functions: Hex O.C. Inverters; Operating voltage: 4.75V - 5.25V