Document Type
Thesis
Date of Award
9-30-1990
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical and Computer Engineering
First Advisor
William N. Carr
Second Advisor
Kenneth Sohn
Third Advisor
N. M. Ravindra
Abstract
This thesis describes the design and operation of a CMOS temperature sensor operating at very low power with an EEPROM error correction scheme including the physical layout. This device is designed for applications requiring very low power including biomedical and optically powered device applications. The sensor output is an analog voltage. The temperature sensing cell is implemented with two BJTs having different emitter areas. An op amp dissipating about 300 micro-watts power is designed and is used to amplify the sensor output voltage with a gain of 85dB. A novel EEPROM is used to correct nonlinearity error of the temperature sensor. This scheme uses hot electron injection and the Fowler-Nordheim tunneling mechanism to decrease and increase the floating gate potential, respectively. Programming is done through a bootstrap capacitor and dedicated diode bias control pins. EEPROM error correction is used at three different stages to control (1) the offset voltage, (2) the gain of the op amp, (3) and to correct nonlinearity. The calculated power dissipation is 0.875 to lmW for the entire chip with a 5V power supply based on simulation by SPICE 2G.5 using MOSIS parameters. The measured power dissipation is 0.776mW at 23°C. The physical database is created using the Mentor Graphics Chipgraph editor. The final chip is 2.2mmx 2.2mm including 40 bonding pads. This device was processed using the 2µm CMOS P-well double level poly and double level metal process through the MOSIS silicon foundry brokerage. The experimental and simulated sensitivity of the temperature sensing cell agree closely at 2.3mV/°C and 2.2mV/°C, respectively. In this thesis experimental characterization is presented for the temperature sensor and the EEPROM error correction transistors.
Recommended Citation
Kang, Jin-ku, "Design of a CMOS temperature sensor with EEPROM error correction scheme" (1990). Theses. 2779.
https://digitalcommons.njit.edu/theses/2779
