Nonstuck behaviour of open circuit supply faults in CMOS logic circuits

The authors describe a mechanism which allows CMOS circuits containing a break in a power supply track (referred to as open circuit supply faults) to operate with little change in their performance parameters. In circuits containing such faults, current can be supplied through the substrate or well contacts enabling logic gates to operate at full design speed. Measurements on circuits containing such faults and results of simulations are presented to demonstrate the effect of the fault. The circuits operate normally, although they may be susceptible to latch-up behaviour and may fail in this way. Transient latch-up testing is recommended to detect such faults