Unlike other commercial devices, developing implantable microsystems for biomedical applications requires critical analyses in terms of specifications, technologies, and design techniques because of the devices’ safety and efficacy. As the industry of medical implantable devices develops, lowering the power consumption as much as possible is essential in improving the service time of the battery, which cannot be replaced frequently. Hence, low power design has become the main concern for battery‐powered implants. Biosignals such as EEG and ECG are weak signals, typically ranging from 0.5μV to 5mV with high source impedance and superimposed high level interference and noise. Hence, there is a need of a pre‐amplification stage in the analog front end of a biomedical acquisition system so that these biosignals can be amplified for measurement and testing purposes, without degrading the signal‐to‐noise ratio. The purpose is to provide amplification that is selective to physiological signal, reject noise, and other sources of interference. In this paper, an in‐depth study of various low power pre‐amplifiers proposed for different biomedical applications were made, along with performance comparison in terms of various amplification‐related specifications such as gain, bandwidth, signal‐tonoise ratio, CMRR, and slew rate among other specifications.
