Radiated harmonics characterization of CMOS test chip with on-chip decoupling capacitance

This paper reports experimental results on far-field radiated emission for different on-chip chip power supply networks. Two types of test chips were developed as noise generators. One was with on-chip decoupling capacitance, and the other was without intentional on-chip decoupling capacitance. They were assembled in a CSP (Chip scale package). The effects of on-chip decoupling capacitance on far-field radiated emission were investigated for the operation of core logic circuits and output buffer circuits. Reduced radiated emission was observed for every harmonics for the operation of core logic circuits by the on-chip decoupling capacitance. While, reduced radiated emission was observed for the even-order harmonics for the operation of output buffer circuits due to the existence of on-chip decoupling capacitance.