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Browse Prior Art Database

PASSIVE COMPONENT TESTING USING JTAG

IP.com Disclosure Number: IPCOM000009656D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-09
Document File: 2 page(s) / 77K

Publishing Venue

Motorola

Related People

Steve Price: AUTHOR [+3]

Abstract

This idea adds the ability to test passive compo- nents on a circuit board using the existing STAG standard.

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0 M MO-LA Technical Developments

PASSIVE COMPONENT TESTING USING JTAG

by Steve Price, Simon Crago and Calum Mackinnon

ABSTRACT

  This idea adds the ability to test passive compo- nents on a circuit board using the existing STAG standard.

INTRODUCTION

  This paper describes improvements in the field of passive component testing on digital circuit boards.

PROBLEM(S) TO BE SOLVED

  Digital circuit boards generally contain a large number of passive components such as de-coupling capacitors, pull-up resistors etc. During manufac- ture on a production line it is very easy for a mistake to be made which results in large numbers of boards fitted with the wrong value of resistor or capacitor. This is currently very difficult to detect after the board is made, especially as the surface-mount com- ponents used have no (or barely legible) labeling. The result of an incorrect passive component is gen- erally not seen until later in the board's life when stressed components start to fail.

PROPOSED SOLUTION TO THE PROBLEM(S)

  This idea addresses the problem by adding a tester chip that is fitted onto the board and is con- nected to samples of the values of passive compo-

nents fitted to the board. The sample components (which are in addition to those components used for the design) are taken from the same reel as the parts used on the board, but are only used for the tester component to measure their values.

  Although there are a large number of capaci- tors/resistors on a board, there...