Measurements of EMI susceptibility of precision voltage references

This paper investigates and reports on the susceptibility of commercial voltage references to electromagnetic interference (EMI). Two separate scenarios have been considered. In the first experiment, the interferences are directly injected onto the power supply lines of each voltage reference. In the second measurement, EMI is capacitively coupled to all the pins of the voltage reference under test, including the output, hereby emulating the presence of a neighbouring noisy printed circuit board (PCB) trace. These measurements show that the resulting EMI-induced offset can attain considerable values at critical EMI frequencies, ranging from 30MHz to 100MHz when the EMI is injected into the power supply rails, and 300MHz to 500MHz when EMI is capacitively coupled to all the pins.