Innovative current sensitive differential low noise preamplifier in CMOS

A low noise differential preamplifier is described. A novel circuit is introduced, reducing the 2nd stage noise contribution of a conventional current mirror fed from the differential input stage to negligible amounts by employing a differential cascode. A desirable by-product of the modified circuit is its increased PSRR. The output of the charge sensitive voltage amplifier employed as low noise input stage is reconverted into current by a Y_T amplifier consisting of a CCII-, whose X terminal output impedance is reduced by including it in the feedback loop of the input amplifier, and by augmenting the CCII- by a current follower. The available current gain is 10⁴ at a bandwidth of 80 kHz and a loop transmission of 90 dB