Analog input digital boundary scan cell, comparator, and analog switches
First Claim
1. An analog input boundary scan cell comprising:
- (a) a digital scan cell having a test data input (TDI), a test data output (TDO), a compare input, a first switch output, and a control input;
(b) a comparator having a voltage reference input, a functional input and a compare output coupled to the compare input;
(c) a first analog switch having a control input coupled to the first switch output, a first voltage input at a first voltage, a second voltage input at a second voltage different than the first voltage, and a first switch output; and
(d) a second analog switch having a functional input coupled to the functional input of the comparator, a first switch input coupled to the first switch output, a mode input, and a second switch output.
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Abstract
The disclosure describes a novel method and apparatus for improving interposers that connected stacked die assemblies to system substrates. The improvement includes the addition of IEEE 1149.1 circuitry within interposers to allow simplifying interconnect testing of digital and analog signal connections between the interposer and system substrate it is attached too. The improvement also includes the additional 1149.1 controlled circuitry that allows real time monitoring of voltage supply and ground buses in the interposer. The improvement also includes the additional of 1149.1 controlled circuitry that allows real time monitoring of functional digital and analog input and output signals in the interposer. The improvement also provides the ability to selectively serially link the 1149.1 circuitry in the interposer with 1149.1 circuitry in the die of the stack.
23 Citations
12 Claims
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1. An analog input boundary scan cell comprising:
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(a) a digital scan cell having a test data input (TDI), a test data output (TDO), a compare input, a first switch output, and a control input; (b) a comparator having a voltage reference input, a functional input and a compare output coupled to the compare input; (c) a first analog switch having a control input coupled to the first switch output, a first voltage input at a first voltage, a second voltage input at a second voltage different than the first voltage, and a first switch output; and (d) a second analog switch having a functional input coupled to the functional input of the comparator, a first switch input coupled to the first switch output, a mode input, and a second switch output. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An analog input boundary scan cell comprising:
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(a) a functional input; (b) a functional output selectively coupled to the functional input; (c) a voltage reference input; (d) a test data input; (e) a test data output coupled to the test data input, the functional input, and the voltage reference input; (f) a control input selectively coupling the test data input to the test data output and selectively coupling a combination of the functional input and the voltage reference input to the test data output; (g) a first voltage input at a first voltage selectively coupled to the functional output; (h) a second voltage input at a second voltage different than the first voltage selectively coupled to the functional output; and (i) a mode input selectively coupling the functional input to the functional output and selectively coupling one of the first voltage input and the second voltage input to the functional output. - View Dependent Claims (9, 10, 11, 12)
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Specification