A Large-Scale Multimodal CMOS Biosensor Array With 131,072 Pixels and Code-Division Multiplexed Readout

This letter presents a large-scale fully integrated multimodal sensor array for biological imaging. The 512×256 sensor array can perform spatially resolved electrochemical impedance spectroscopy (EIS) with switching frequencies up to 100 MHz, acquire multicolor optical images, and sense pH using titanium nitride (TiN) ion sensitive field effect transistors (ISFETs). The chip features code-division multiplexed (CDM) readout of groups of pixels simultaneously, enabling extended integration times at a given frame rate. The system is implemented in 180-nm CMOS with 9.5 μm × 11.5 μm pixels. Its overall fill factor is 57%, including peripheral control and readout circuits, yielding a widefield spatially resolved multimodal biosensing platform for advanced cell culture applications.