Development of integrated circuits for readout of microelectrode arrays to image neuronal activity in live retinal tissue

Two multichannel Application Specific Integrated Circuits (ASICs) for extracellular recording of neuronal signals from live retinal tissues using microelectrode arrays have been developed. In this paper we discuss the requirements concerning the IC parameters and characteristics as well as present the designs and the test results. The required electronic functionality has been divided into two ASICs: PLAT-64 and NEURO-64 realized in a 0.7 /spl mu/m CMOS process. The PLAT-64 chip comprises 64 capacitors of 150 pF each, and 64 addressable and controlled DC current sources for platinization of electrodes. The NEURO-64 chip comprises 64 channels of low noise amplifiers and bandpass filters and an analog multiplexer. The low noise performance of the preamplifier has been achieved by careful selection of a CMOS process and by proper sizing and biasing of the input devices. The required lower cut-off frequency of 20 Hz has been obtained by employing a novel RC filter structure.