PreAmp with 2nd order highpass and differential output pulser 3rd order lowpass

amp out f z =0 amp out f z =1MHz filter out f p =15MHz

filter out amp out f z =0

Noise tranfer function amp out filter out + 6dB

Conclusions - PreAmp for 12 bit resolution = 72 dB SNR and THD => 72 dB loop gain + 34 dB closed loop gain = 106 f T = 40 MHz - 1 LSB = 245 µV => 310 Cfb = 200fF - Thermal noise of feedback Cfb =200fF = 150 µV (kT/C) - Input referred noise of PreAmp is amplified by A= 1+ Cfb/ Cshunt = ~100 ( 40dB) => 150 µV / 100 = 1.5 µV !!! (including pick up) - Differential input helps to reduce pick up of noise irradiation - Separate PreAmp chip should be attached very close to detector pad in order to reduce Cshunt - Pulse shaping by zero of PreAmp transfer function reduces required dynamic range and hence saves power - High order lowpass (Gm/C) filter is natural companion of AD-converter/digital chip