Document Type
Thesis
Date of Award
1-31-1989
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical Engineering
First Advisor
William N. Carr
Second Advisor
Durgamadhab Misra
Third Advisor
N. M. Ravindra
Abstract
This thesis presents the design of a temperature sensor circuit including sensor, differential amplifier, and a memory element for gallium arsenide IC standard cell applications. A standard 1-um depletion-mode GaAs MESFET technology has been used for the design of the circuit. The circuit is intended to be used as a standard cell in GaAs les providing an alarm when the sensor temperature reaches 125 °C. The circuit includes a NAND latch which is set when the chip cell temperature reaches 125 °C. The output of the latch can be sensed by additional circuits (on or off the GaAs chip) which initiate systems-level cooling or shut clown. For sensing the temperature, a GaAs diffused diode pair is employed in which diode areas are ratioed (8 to 1). This enables the diodes to provide a differential voltage which is proportional to absolute temperature. The circuit simulation was done using SPICE3B.1 software installed on VAX station II/GPX hardware in Ultrix V2.0 environment. The Valid Logic Systems CAE software has been used for the schematic capture and GaAs physical layout. The photolithography mask set utilizes 8 layers - active area(N-), source & drain(N+), ohmic contact, Schottky gate metal, metal 1, metal 2, intermetal via and passivation. The total area of the sensor cell is 195x195 square microns. The worst case error demonstrated by the sensor circuit due to the cumulative effect of ±5% variations in the MESFET threshold voltage, diode junction potential, power supply voltage, resistor layout mismatch and ±10% variation in the MESFET transconductance was found to be 7.7 °C.
Recommended Citation
Gutala, Raviprakash Raviprakash, "Design of a temperature sensor for gallium arsenide ic applications" (1989). Theses. 2778.
https://digitalcommons.njit.edu/theses/2778
