Single chip ASICs for smart sensor signal conditioning

Innovative circuit design techniques based on standard CMOS wafer fabrication processes are enabling sensor products to incorporate a higher level of intelligence while simultaneously reducing cost and product size. Error correction and output calibration for sensor products has traditionally been implemented by laser trimming thick film passive components in a hybrid circuit containing discrete components for signal conditioning. This “analog trimming” approach has many limitations, including high labour and material costs since the process is manual, limited product accuracy, large physical size, high component count and long term performance drifts. ISS has developed a new approach to sensor signal conditioning that is based on “electronic trimming.” In this “one sensor, one ASIC” approach, a fully integrated, single chip integrated circuit replaces a hybrid circuit containing many passive components. Digital calibration coefficients, stored in on-chip non-volatile memory, eliminate the need for external components or laser trimming. As a result, there are dramatic improvements in performance and cost