Design and analysis of ultra-robust analog library cells for aerospace applications

• Main Author: Chen, Ke.
• Other Authors: Chang Joseph Sylvester
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electronic circuits
• Online Access: http://hdl.handle.net/10356/54523
• Institution: Nanyang Technological University

Ionizing radiation, such as high energy electromagnetic radiation and particle radiation, has an impact to the integrated circuit using commercial CMOS process which is susceptible to damage or malfunction caused by radiation effects. This makes it very challenging for integrated circuit design applied to the outer space, nuclear reactor or other radiation environment. However, due to the development of the CMOS technology, deep submicron device with ultra-thin silicon oxide has a great resistance towards the ionizing radiation. Moreover, Radiation Hardened techniques such as shielding, using insulating substrate instead of usual semiconductor wafers, are applied to enhance robustness under the radiation effect. Radiation Hardened by design, in another way, provides the solution through circuit schematic design which will be the main concern in this work. Digital to Analog Converter (DAC) is a device that converts digital signal to analog signal and widely used in the generation of audio/video signals. DAC is an essential block for building the integrated circuit. Under radiation environment, the performance of the DAC is affected and output signal suffers continuous or transient distortion. Thus a RHDB DAC is required in order to be used in the radiation environment. In this project, a RHDB DAC topology is proposed. The circuit is designed using 65nm GlobalFoundries with low power supply of 1.2V. Two essential building blocks of DAC, bandgap reference and amplifier, are designed with radiation tolerance and ability to work under large temperature variation. The bandgap reference has a temperature coefficient less than 50ppm/ ˚C within 40 ˚C to 125 ˚C, a Power Supply Rejection Ratio (PSRR) higher than 60dB at DC condition and power consumption less than 150μW. The amplifier has an open loop gain of 78dB, a bandwidth of 80MHz and phase margin more than 70 degree. In conclusion, the performance and features of the proposed design fulfill the requirement of the aerospace application.