A programmable gain amplifier based on a two-level CNTFET op amp with optimized trans-conductance to drain current ratio

Abstract

A cardiac biomarker (CB) is an important substance released into the blood during heart damage. CB measurements help in the detection of concentric levels in cardiac troponin I. The increased troponin level in the blood can lead to the major cause of cardiac injury. Hence it is necessary to monitor the troponin level of blood. Accurate troponin I detection sensors detect the troponin level in blood. The biosensor signal is converted into an electrical signal of very low voltages. However, these electrical signals are too low. Hence, a bio-medical amplifier is introduced with analog to digital converters and compressors to amplify, capture, transfer and digitize the biosensor signal with less power and area consumption. A bio-amplifier is presented with programmable bandwidth and gain, but the task is challenging. Hence, a fully balanced bio-medical gain amplifier using a two-level CNTFET based operational amplifier (op-amp) (BGA-2C-opamp) is proposed in this work. This particular work uses two stages of CNTFET-based op-amp and presents an input capacitor for blocking the DC offset voltages. This coupling input capacitor operates the bio-medical amplifier gain using an extra load capacitor at the output. The coupling feedback resistor and capacitor are used in this amplification stage to provide a small pole frequency. The proportion of input and the feedback capacitors determines the gain of the amplification stage. To develop a two stage CNTFET-based op-amps, the trans-conductance to drain current ratio measurement is used in this case. Moreover, the bias currents of the quasi-resistors used in the feedback circuit are adjusted to achieve the cut-off programmability. The proposed BGA-2C op-amps are carried out in the cadence Virtuoso tool and analyze the proposed system’s effectiveness in magnitude response, phase response, transient response, gain, total harmonic distortion, input referred noise, phase margin, common mode rejection ratio and power supply rejection ratio. In addition to this, the performance measures of delay (D), power (p) and power delay product are examined under different chirality vectors; also, the Monte Carlo analysis is examined.