Non-contact test access for Surface Mount Technology IEEE 1149.1-1990


Mechanical and chemical process challenges initially limited acceptance of surface-mount technology (SMT). As those challenges have been overcome, another obstacle has become apparent: electronic test access. Through-hole components on a 100mil grid have allowed physical access. SMT, which has provided new levels of packing density has also denied physical test access. To overcome this challenge, the Institute of Electrical and Electronics Engineers (IEEE) has sponsored a new standard, IEEE 1149.1-1990, the Standard Test Access Port and Boundary-Scan Architecture. This application note describes that standard by citing examples of the process.