Designed-In Protection and Product Testing

Abstract

Considerable effort is required to minimize ESD effects in manufacturing. However, the control program described in this book would be largely ineffective without some protection built into the devices. Manufacturing using metal oxide semiconductor (MOS) devices without specific protection circuitry would be extremely expensive if not impossible. Furthermore, once the devices leave the factory in circuit assemblies, they again become vulnerable during installation, maintenance, and repair. These functions are often performed by someone other than the equipment manufacturer. Thus, protection is required to survive this more hostile environment. Since performance requirements may limit the on-chip protection of some devices, additional protection may be required at the PWB assembly or system level. Special design techniques are also required to protect operating equipment from experiencing ESD-induced upset or soft errors as well as errors in data transmission.