High-Performance ADC for Particle Accelerator Instrumentation Applications

A critical aspect in Particle Accelerator Instrumentation is the precise, real-time control of the high- energy particle beams used to create the conditions required for sub-atomic physics experiments. The accelerator instrumentation systems require digital control and feedback with extremely high linearity and dynamic range to achieve system performance targets. In addition, with the added requirements of radiation hardness (because of the devices proximity to the particle beam) and low power (because of the heat generated by densely packed high performance electronics), the analog- to-digital data converter (ADC) is a critical chokepoint that must meet demanding standards. An innovative high performance ADC will be designed and fabricated as a single chip. Based on a novel time-interleaved pipeline architecture developed in Phase I, the ADC will withstand high levels of radiation while providing overall converter performance that exceeds the best conventional (non- rad-hard) ADCs available on the market today. The combinations of performance and radiation tolerance make this ADC ideal to incorporate into particle accelerator instrumentation applications. Phase I saw the design, development, and simulation of a behavioral model of the complete ADC, along with transistor-level designs of key subcircuits. The most important subcircuit, a 3 GS/s track- and-hold amplifier was designed and simulated in the most-advanced silicon germanium fabrication process with accurate transistor models, and its clock jitter, distortion and noise performance clearly exceeds any reported results. A simple test chip was also sent out for fabrication (an achievement beyond the Phase I requirements), and will be verified/tested at the start of Phase II. This program will lead to a programmable, high speed (500 MS/s 3 GS/s), high resolution (12-14 bits) ADC for use in particle accelerator instrumentation applications. The ADC will be highly linear with an INL and DNL of no more than 0.5 LSB, an operating temperature range of at least -10 to 80C, a very high effective number of bits (ENOB) of 11.0, and a total ionization dose (TID) rating of 1 Mrad. These characteristics exceed the requirements of Topic 44g of the DOE SBIR solicitation (12-14 bits, 0.5 2 GS/s) and make this ADC highly suitable for use in particle accelerator instrumentation applications systems, even in the systems where radiation exposure would otherwise degrade performance. Commercial Applications and Other Benefits: This ADC will be well-suited for other DOE nuclear physics and high-energy physics instrumentation. In addition, there is a wide range of both commercial and government applications that demand the combined high performance and radiation tolerance achieved by this design. These include space- based applications such as software-defined radio and satellite systems. The design can be further optimized for conventional, non-rad-hard applications (thus reducing the power and area requirements and boosting even further the circuit performance) to address the most advanced radar and communications systems