The Intersil HCTS139MS is a radiation hardened 2 to 4 line decoder/demultiplexer with an active low enable. Data on the select inputs cause one of the four normally high outputs to go to a low logic level. The demultiplexing function is performed by using the enable input as the data input. The HCTS139MS utilizes advanced CMOS/SOS technology to achieve high-speed operation. This device is a member of the radiation hardened, high-speed, CMOS/SOS logic family with TTL input compatibility. The HCTS139MS is supplied in a 16-lead ceramic flatpack (K suffix) or an SBDIP package (D suffix).