Built-in Current Sensor for High Speed Transient Current Testing in Analog CMOS Circuits

In this paper, we present a new built-in current sensor (BICS) for high speed, low voltage degradation transient current (I_DDT) testing. This sensor has been designed using forward bias technique to limit the supply voltage degradation caused during transient current peaks to 2% of the supply voltage. A CMOS operational amplifier designed for operation at plusmn2.5 V in 0.5 mum n-well CMOS process is used as the circuit under test (CUT). The faults simulating possible short and bridging defects are introduced using the fault injection transistors (FIT). A total of twenty short faults have been introduced into the CUT and nineteen of them were detected, giving 95% fault coverage.