FREQUENCY-DEPENDENCE OF AC-INTERFERENCE SUSCEPTIBILITY IN DIGITAL ICS

A study is made of the frequency dependence of AC-interference suscept ibility in ICs. The effects of AC energy, picked up from the environme nt by a TTL IC, on the response of the victim are analysed experimenta lly and numerically. The experimental results of NAND gates interfered by AC signals with frequencies below 450 MHz are shown. Numerical ana lysis is carried out through the aid of a SPICE simulation tool. Simul ation results are in good agreement with the experimental data. Moreov er, a simple formula for predicting the threshold level of interferenc e susceptibility is obtained for the 7400 NAND gate.