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Adaptive Boundary-scan chain for different packages

IP.com Disclosure Number: IPCOM000239043D
Publication Date: 2014-Oct-03
Document File: 3 page(s) / 87K

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper describe an adaptive Boundary-scan chain architecture which automatically bypass Boundary-scan cells whose I/O are not bonded out (referred as “conditional I/O”) in small packages. A detection circuit to distinguish conditional I/O and their boundary scan cells is introduced so that boundary scan chain can be self adaptive for different packages.

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Adaptive Boundary-scan chain for different packages

Abstract – This paper describe an adaptive Boundary-scan chain architecture which automatically bypass Boundary-scan cells whose I/O are not bonded out (referred as “conditional I/O”) in small packages. A detection circuit to distinguish conditional I/O and their boundary scan cells is introduced so that boundary scan chain can be self adaptive for different packages.

The IEEE 1149 Test Access Port and JTAG Boundary-scan architecture are commonly used for circuit board level test and DC characterization test. The IEEE1149 compliant Boundary-scan chain includes boundary scan cells which make I/O pins controllable and observable.

Fig 1. Boundary-scan architecture

Multiple packages with different features may be applied for same integrated circuit design. Some features and corresponding I/O are invisible (not enabled) on certain packages such as smaller packages.

To meet high boundary-scan coverage, all boundary-scan cells, including those whose I/O are not bonded out in small packages, need to be kept on chain for full package. While, for smaller packages, problem arises about how to handle boundary-scan cells whose I/O are not bonded out. To save cost and simplify design, IC (integrated circuit) design doesn’t want to power the un-bonded I/O internally, and IC device customers don’t want to power them on circuit board with extra costs.

We introduce an adaptive boundary-scan chain architecture that automatically bypasses boundary-scan cells whose I/O are not bonded out (referred...