Electromagnetic Compatibility Modeling in Low-Noise Medical Sensor Interfaces

Investigations on the electromagnetic behaviour of a low-power amplifier are led using the extended-integrated circuit emission model (ICEM). This modeling approach is proposed on a mixed-signal (analog/digital) CMOS 0.18 mum circuit dedicated to neural signal recording. This ICEM allows coarse and fast studies of the electromagnetic compatibility of CMOS devices especially in characterizing the coupling phenomena that occurs at each building block inside the whole chip. ICEM simulations of power and ground bounces are more than 500 times faster than complete SPICE ones with a correct accuracy for first electromagnetic compatibility investigations. This quick modeling method allows for checking many different design or simulation configurations. For example, some simulation results show that substrate interactions and power/ground crosstalk increase the noise level of the low-noise amplifier, in particular in its low frequency domain.