Analog circuit observer blocks

Ramesh Harjani, Bapiraju Vinnakota

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Analog and mixed-signal integrated circuits (IC's) are rapidly becoming more complex. In addition to the traditional problems associated with testing IC's, such as limited controllability and observability, analog and mixed-signal test is vulnerable to measurement induced errors. Constraints on measuring analog signals significantly increase the complexity and cost of testers for such circuits. In this paper, we introduce a design for test technique for analog and mixed-signal circuits, analog circuit observer blocks (ACOB's). ACOB's are structures designed to reduce the need for precision in measuring analog signals during circuit test. The primary technique used is that of encoding the data in the circuit (only during the test phase). ACOB's potentially offer a number of advantages over conventional offchip test techniques such as reduced tester complexity, smaller measurement induced errors and increased observability. ACOB schemes will necessarily have to be tailored to the type of circuit targeted. We present two ACOB schemes, one for the class of fully differential circuits, the second for pipelined analog-to-digital converters. In both cases, the ACOB schemes are shown to offer substantial benefits.

Original languageEnglish (US)
Pages (from-to)154-163
Number of pages10
JournalIEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing
Issue number3
StatePublished - 1997

Bibliographical note

Funding Information:
Manuscript received June 20, 1994; revised September 28, 1995. This work was supported in part by a Grant from NST MIP 9501499. This paper was recommended by Associate Editor M. Soma. The authors are with the Department of Electrical Engineering, University of Minnesota, Minneapolis, MN 55455 USA. Publisher Item Identifier S 1057-7130(97)01687-X.

Funding Information:
Dr. Vinnakota received the Career award from the National Science Foundation in 1995.

Copyright 2011 Elsevier B.V., All rights reserved.


  • Analog test, code-based test, design for test, 1c test, mixed-signal test


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