Research on Anti-EMI Capability of Current Steering Logic CMOS Circuit

With the rapid development of technology, electromagnetic radiation has become universal but fatal to circuits. Circuits stabilities against EMI has become a major sign to judge circuits designing. In this paper, by using theoretical analysis and real circuit testing methods, it is proven that the current steering logic CMOS circuits has stronger anti-electromagnetic interference (anti-EMI) capabilities than traditional voltage CMOS circuits. Firstly, using field-line coupling theory, current signals in transmission lines are proven to be less easily interfered by electromagnetic radiation than voltage signals, which indicates its stronger anti-EMI capability than voltage signal in the line, theoretically. Further, NAND gate and quaternary counter PCB circuits were made for both current steering logic CMOS and voltage CMOS circuit. Using the Tesla coil and vector network analyzer (VNA) as electromagnetic radiation source respectively, we verified that current steering logic CMOS circuit has stronger anti-EMI capability than voltage CMOS circuit. By using ZNB20 VNA and standard gain antenna for electromagnetic radiation output, current steering logic CMOS circuits can keep functional under stronger electromagnetic radiation than voltage CMOS circuits. The maximum radiation power for current steering logic CMOS circuits to keep functional is up to hundreds of times more than the voltage CMOS circuits. Thus, compared with voltage CMOS circuits, current steering logic CMOS circuits are more suitable to work under strong electromagnetic environment.