NPN Sziklai pair small-signal amplifier for high gain low noise submicron voltage recorder

Small signal-to-noise ratio (SNR) and multiple noise sources, coupled with very weak signal amplitudes of bio signals make brain-computer interface (BCI) application studies a challenging task. The front-end recorder amplifiers receive very-weak (few μV) from high impedance electrodes for efficient processing such low frequency (<1 kHz) gain amplifier operating voltage total harmonic distortion (THD) is required. Existing suffer problem non-linearity common mode rejection. A good sense at predeceasing stage can solve this problem. Utilizing amplification factor Sziklai Pair, paper proposes two circuit topologies common-emitter common-collector negative-positive-negative (NPN) Pair small suitable use in preamplifier stages acquisition circuit. Present study provides broad-spectrum analysis these covering effect additional biasing resistance RA, variation ‘ideal forward maximum beta’ β, temperature dependency, sensitivity phase variation. tunable capability first topology makes it candidate wide variety other applications. operates on input range (0.1μV-6mV) whereas the second works 100 μV-11 mV voltage.