This paper exhibits the comparative design of front end analog amplifier for neural acquisition system, neural amplifier employed for recording of neural signals involves in the measurement of weak neural potentials or spikes, performance of whole recording system is affected by performance of neural amplifiers. The precise response of neural amplifier is contaminated due to the coupling of noise signals with signal of interest, which proves to be limiting factor. The comparative design of

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... l amplifier is presented based on two different architectures as CMFB OTA and DTMOS based VDTA in order to compare the performance parameters to obtain the best suited design for neural amplifier which positively satisfies the design parameters of neural amplifier such as noise, power dissipation, CMRR,PSRR & Gain. Based on comparative analysis, CMFB OTA exhibits the best suited results which are implemented in 0.35µm with gain of 63.89dB, noise 100uV/√Hz, NEF 3.0, power dissipation of 1.00*10 -10 W, CMRR as 110dB and PSRR as 81dB. Index Terms: Low voltage signals, Low power consumption, High gain, Bio-Medical Interface (BMI),Low Noise Architecture, Weak Neural Signals, DTMOS, CMFB, OTA, VDTA. I. INTRODUCTION Neural potentials or spikes is responsible to carry the vital information about the neural activities of patient which enables the clinicians or doctors to diagnose and helpful to provide the desired treatment of disease such as brain injuries as well neural disabilities like epilepsy and Parkinson's disease. Neural signals posse's different amplitude and frequency characteristics. Neural signals are basically classifies in two categories includes neural spikes and local field potentials. Neural spikes produced by the neurons categorized in the frequency range of 300Hz -5kHz, amplitude of neural signal comes under the range of 1µV and 100µV. There is need to bring the improvement in the healthcare quality as a result proper signal acquisition system is needed which proves to provide precise results for variety of neural signals lying under various amplitude and frequency range. In order to attain the desired performance of acquisition system, quality of neural signals recorded are required to be improved which is highly dependent on noise which proves to be limiting factor. A low noise or neural amplifier is equipped at the primary stage of receiver. Low noise amplifier is the predominant part for recording good quality of neural signal sensing system to process and analyze low voltage signals. Commonly used non-invasive method to record the neurological activities by employing electrodes on scalp is Electroencephalogram (EEG). Neural acquisition system block diagram is shown in figure 1.Interfacing circuitry with the nervous system is considered to be the difficult task. The regular advancement in the field of neural interfacing has enhanced the proper understanding of central nervous system which has enabled to develop potentially therapeutic and prosthetic applications.