Research Of The Testing Of The High Performance Low Power Sigma-Delta Analog-to-Digital Converter

With the rapid development of modern electronic information technology, the analog and digital interface circuits ADC are also getting continuous development towards the direction of high-precision. The followed related test requirements are getting higher and higher. Now the test costs have accounted for the total cost of the chip more than30%, and this proportion is still growing. The integrated circuit testing industry has become an indispensable and very important aspect. Therefore test methods and effective research are of great practical significance.This selected TI’s20-bit DDC112U with Sigma-Delta structure ADC as the high-performance low-power ADC sampling. Through referring to foreign ADC evaluation board design experience, make a careful study of the matching relationship between different parts. A variety of components required for the evaluation boards were selected and the purchased. Then use the relevant software for test board schematic drawing, and further considering the high-performance PCB design and manufacture a variety of issues related to the final design and produce high-performance DDC112U test board. Based on this test board, use the existing laboratory instruments and equipment to build the ADC test system. Through establishing reasonable and effective test plan to test DDC112U’s important technical parameters, study and explore an effective way of high performance ADC important parameters test technology. Main content and results include two aspects:1. First, through careful study DDC112U data sheet to fully understand the test chip. Then analyze the important parameter, working principle and basic structure of Σ-△ADC, which is the core module of DDC112U, and modeling and simulating under ideal and non-ideal circumstance respectively, focusing on the important parameters of the ADC analysis indicators and corresponding test methods. Identified DDC112U each circuit module test board composition, and study the reference voltage and clock generation circuit test chip and its main modules and the main indicators of the relationship. A variety of components required for the evaluation board were selected and the purchased with the DDC112U test board schematics at the same time.2. Detailed study the PCB design process of DDC112U test board, full consideration of signal integrity, power integrity and electromagnetic compatibility and other related factors, on the basis then design and welded DDC112U test board. Establish the circuit module to meet the requirements of the basic indicators. Then make use of existing experimental equipment to build a test system, and develop a reasonable testing program, thus completing the basic parameters of DDC112U chip testing and evaluation. The results also demonstrate the feasibility of these test ideas.