Hi,
We are developing a biomedical device that measures EEG and skin impedance (GSR/EDA). We are looking for an IC specifically designed for AC-based skin impedance measurement.
We initially evaluated the AD5933, but it cannot generate an excitation frequency of around 100 Hz, which is required for our application. Therefore, we are looking for an alternative IC that supports low-frequency impedance measurements.
We also reviewed the AD5940, which appears to meet our requirements. However, the official evaluation kit is quite expensive for our current evaluation.
We have tested a conventional DC-based GSR circuit, but the measured GSR signal contains noticeable ECG interference, instead of representing only changes in skin impedance. Our understanding is that using an AC excitation signal should help reduce electrode polarization effects and improve the accuracy of skin impedance measurements.
We would appreciate your suggestions for an IC or analog front-end that:
* Generates a low-frequency AC excitation (around 100 Hz).
* Is suitable for skin impedance/GSR/EDA measurements.
* Can be integrated into a custom PCB.
* Is more affordable than the AD5940 evaluation platform.
Has anyone worked on a similar application or can recommend suitable ICs, reference designs, or application notes?
Thank you.