Experimental Verification of Power Supply Noise Modeling for EMI Analysis through On-Board and On-Chip Noise Measurements

Abstract

Power supply noise waveforms are acquired in a voltage domain by an on-chip monitor at resolutions of 0.3 ns/1.2 mV, in a digital test circuit consisting of 0.18-μm CMOS standard logic cells. Concurrently, magnetic field variation on a printed circuit board (PCB) due to power supply current of the test circuit is measured by an off-chip magnetic probing technique. An equivalent circuit model that unifies on- and off-chip impedance network of the entire test setup for EMI analysis is used for calculating the on-chip voltage-mode power supply noise from the off-chip magnetic field measurements. We have confirmed excellent consistency in frequency components of power supply noises up to 300MHz among those derived by the on-chip direct sensing and the off-chip magnetic probing techniques. These results not only validate the state-of-the art EMI analysis methodology but also promise its connectivity with on-chip power supply integrity analysis at the integrated circuit level, for the first time in both technical fields.