Method and apparatus for testing integrated circuits in a mixed-signal environment
First Claim
1. Apparatus for measuring electrical component means which are external to and interconnected with first and second integrated circuit devices which devices include first and second analog circuits respectively, said apparatus comprising a first and a second analog test bus means included in said first and second devices respectively, multiplex means included in each of said devices for selectively connecting said component means either to said analog circuit means or to said analog test bus means, test circuit means connected with said first and second test bus means and including a source for supplying a current to said component means when said component means is connected with said test bus means and detector means for determining the value of said component means.
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Accused Products
Abstract
A method and apparatus is disclosed for testing integrated circuit interconnect and measuring the value of passive component interconnecting the IC'"'"'s. Each IC includes both analog and digital circuitry and is provided with a test access port and boundary scan architecture for selectively connecting components to an analog test bus and for testing for the integrity of interconnections. When connected with the test bus, a constant current is supplied to the component and the resulting voltage developed across the bus is used for identifying the value of the component. In a second embodiment each IC includes a pair of buses which permits measurement of the impedance of the switches connecting the components to the test bus.
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Citations
22 Claims
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1. Apparatus for measuring electrical component means which are external to and interconnected with first and second integrated circuit devices which devices include first and second analog circuits respectively, said apparatus comprising a first and a second analog test bus means included in said first and second devices respectively, multiplex means included in each of said devices for selectively connecting said component means either to said analog circuit means or to said analog test bus means, test circuit means connected with said first and second test bus means and including a source for supplying a current to said component means when said component means is connected with said test bus means and detector means for determining the value of said component means.
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2. An integrated circuit device, comprising:
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a) core analog circuitry; b) an input/output pin; c) first and second analog test buses; d) switch means, comprising; i) a first switch connecting said pin to said core analog circuitry; ii) a second switch connecting said pin to said first analog test bus; iii) a third switch conneting said pin to said second analog test bus; and e) test circuitry for controlling the state of said switches so as to disconnect said pin from said core analog circuitry and selectively connect said pin with said first and/or second test buses. - View Dependent Claims (3, 4, 5, 6)
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7. An integrated circuit, comprising:
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a) a core; b) a plurality of externally accessible electrical contact points comprising a first contact point; c) means for disconnecting the first contact point from the core; d) means for delivering a test stimulus to the first contact point; e) means for obtaining an analog response to the test stimulus; and f) means for connecting the first contact point to an integrated circuit operating voltage or reference relative to the test stimulus. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of testing one or more electrical components which are interconnected between two or more electrical contact points located on one or more integrated circuits, comprising the steps of:
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a) programming all integrated circuits having an electrical contact point connected to the one or more electrical components to disconnect their cores from said electrical contact points; b) programming at least one of the integrated circuits having an electrical contact point connected to the one or more electrical components, contact A, to connect contact A to a reference; c) programming one of the integrated circuits having an electrical contact point connected to the one or more electrical components, contact B, to deliver a test stimulus, relative to the reference, to contact B; d) programming one or more of the integrated circuits having an electrical contact point connected to the one or more electrical components to output analog responses to the test stimulus; and e) calculating values of the one or more electrical components using the analog responses to the test stimulus. - View Dependent Claims (19, 20, 21, 22)
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Specification