The Impedance Spectroscopy ASIC is used for geophysical characterisation applications. This high linearity RxTx SoC achieves high performance in a multi-sensor environment where multiple ASICs coexist working at different channel frequencies. An integrated 400MHz Fractional-N PLL ensures optimum channel selection and low phase noise detection. An input mux can select between multiple inputs while maintaining low crosstalk and high SNR. The ASIC covers a wide input bandwidth (1MHz-40MHz) and dynamic range. The ASIC works over an extended temperature range from -40 to +220 degrees Celsius.