Title :
Integrated 1.2 μm CMOS photodiodes, transimpedance amplifier, 12 bits A/D converter, and DSP interface for microinstrument applications
Author :
Chen, Wuping ; Duan, Hongwei ; Jones, Stephen H.
Author_Institution :
Dept. of Electr. Eng., Virginia Univ., Charlottesville, VA, USA
Abstract :
Integrated CMOS photodiodes, transimpedance amplifier and dual-slope ADC are designed and fabricated in 1.2 μm AMI ABN MOSIS process. The quantum efficiency of n-diffusion p-base junction photodiode with size 200 μm×200 μm is 21.7%. The transimpedance amplifier uses T-feedback to realize large equivalent feedback resistance. The 12-bit dual-slope A/D converter with size 450 μm×950 μm, an integrating resistor of 273 K, and an external capacitor of 1.5 nF has conversion time from 0.41 ms to 0.81 ms when fclock=10 MHz. 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
Keywords :
analogue-digital conversion; biomedical electronics; computerised monitoring; mixed analogue-digital integrated circuits; photodiodes; 0.41 to 0.81 ms; 1.2 micron; 10 MHz; 12 bit; 1950 micron; 200 micron; 21.7 percent; 450 m; A/D converter; AMI ABN MOSIS process; CMOS photodiodes; DSP interface; T-feedback; breathing rate monitor; conversion time; dual-slope ADC; equivalent feedback resistance; heart rate monitor; integral nonlinearity error; microinstrument applications; n-diffusion p-base junction photodiode; offset error; quantum efficiency; transimpedance amplifier; Ambient intelligence; Application specific integrated circuits; Biomedical monitoring; Digital signal processing; Heart rate; Heart rate measurement; Optical amplifiers; Photodiodes; Remote monitoring; Resistors;
Conference_Titel :
Circuits and Systems, 1999. ISCAS '99. Proceedings of the 1999 IEEE International Symposium on
Conference_Location :
Orlando, FL
Print_ISBN :
0-7803-5471-0
DOI :
10.1109/ISCAS.1999.777840
