A current sensing circuit for IDDQ testing

This paper presents a new built-in current sensor (BICS) that detects defects using the current testing technique in CMOS integrated circuits. This circuit employs cross-coupled PMOS transistor, it is used as a current comparator. The proposed circuit is a negligible impact on the performance of the circuit under test (CUT). In addition, no extra power dissipation and high-speed fault detection are achieved. It can be applicable deep sub-micron process. The validity and effectiveness are verified through the HSPICE simulation on circuits with defects. The entire area of the test chip is 116×65 μm². The BICS occupies only 41×17 μm² of area in the test chip. The area overhead of the BICS versus the entire chip is about 9.2%. The chip was fabricated with Hynix 0.35 μm 2-poly 4-metal standard CMOS technology.