Low-distortion current-mode companding integrator operating at f T of BJT

The authors show that the nonlinear V-I large-signal characteristic of the n-p-n transistor, combined with its nonlinear base-emitter capacitance, can be directly exploited to realise a transistor-only instantaneous current-mode integrator. The resulting circuit offers low distortion and the ability to operate at very high frequency, i.e. in the range of the f_T of the BJT device