Characterization of the Texas Instruments Inc AFE4500 analog front end chip for wearable bioimpedance applications

The proliferation of wearable health monitors has prompted the investigation of bioimpedance (BioZ) to deliver meaningful health data. The Texas Instruments Analog Front End 4500 (AFE4500) is equipped with BioZ functionality but has not been characterized. This study provides an initial characterization of the AFE4500's BioZ function in RC loads. We evaluate and report the performance of the AFE4500 for wearable body composition monitoring. The AFE4500 exhibits the greatest precision with higher excitation currents and low BioZ sampling frequency. The lowest standard deviation (0.20 Ω) was achieved at 6.67 samples per second. AFE4500 measurements showed the lowest root mean square error of 4.37 Ω compared to ground truth at 50 kHz excitation. The AFE4500 measurement precision and small form factor prepare it for physiological monitoring in wearable body composition assessment using smartwatches and rings.