A bio-field effect transistor (bioFET) system includes a bioFET configured to receive to a first voltage signal and output a current signal, where the current signal varies exponentially with respect to the first voltage signal. A logarithmic current-to-time converter is connected to the bioFET and is configured to receive the current signal and convert the current signal to a time domain signal. The time domain signal varies logarithmically with respect to the current signal, such that the time domain signal varies linearly with respect to the first voltage signal.