Integrated 1.2um CMOS photodiodes, transimpedance amplifier, 12bits A/D converter, and DSP interface for microinstrument applications

摘要

Integrated CMOS photodiodes, transimpedance amplifier and dual-slope ADC are designed and fabricated in 1.2um AMI ABN MOSIS process. The quantum efficiency of n-diffusion phase junction photodiode with size 200um×200um is 21.7%. Thetransimpedance amplifier uses T-feedback to realize large equivalent feedback resistance. The 12-bit dual-slope A/D converter with size 450um×1950um, a integrating resistor of 273K, and an external capacitor of 1.5nF has conversion time from 0.41ms to0.8lms when fclock=l0MHz. The offset error is 5 LSB and the integral nonlinearity error is 0.4% of full scale. The chip derived from this project is successfully used in a novel microinstrument for heart rate and breathing rate monitor.