A technique for testing CMOS analog integrated circuits is presented which is based on an analysis of the noise behavior of the circuit under test (CUT). The technique is simple and new. The CUT in the present work is an integrated CMOS amplifier circuit designed in a standard 1.5 μm n-well CMOS process for operation at ±;2.5 V. The bridging faults simulating possible manufacturing defects have been introduced using fault injection transistors. The faults in the CUT are detected by observing the variation in the noise at the output of CUT, which is the sum of noise contributed from each component in the circuit. An analytical noise model of the CUT has been developed with and without faults and results are compared with the corresponding data obtained from the simulation studies using SPICE.
Proc. SPIE. 5844, Noise in Devices and Circuits III
KEYWORDS: Amplifiers, Power supplies, Monte Carlo methods, Integrated circuits, Field effect transistors, Picosecond phenomena, Analog electronics, Tolerancing, Decision support systems, Device simulation
A technique integrating the noise analysis based testing and the conventional power supply current testing of CMOS analog integrated circuits is presented for bridging type faults due to manufacturing defects. The circuit under test (CUT) is a CMOS amplifier designed for operation at ± 2.5 V and implemented in 1.5 μm CMOS process. The faults simulating possible manufacturing defects have been introduced using the fault injection transistors. The amplifier circuit is analyzed and simulated in SPICE for its performance with and without fault injections. The faults in the CUT are identified by observing the variation in the equivalent noise voltage at the output of CUT. In power supply current testing, the current (IPS) through the power supply voltage, VDD is measured under the application of an AC input stimulus. The effect of parametric variation is taken into consideration by determining the tolerance limit using the Monte-Carlo analysis. The fault is identified if the power supply current, IPS lies outside the deviation given by Monte-Carlo analysis. Simulation results are in close agreement with the corresponding experimental values.