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US 5,673,277 AGranted
Scan test circuit using fast transmission gate switch
AssigneeQuality Semiconductor, Inc.
InventorsZwie Amitai, Mark Muegge
Life of this patent
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Abstract
A fast transmission, integrated circuit switching device responsive to at least one external on/off control signal, and including a first input/output node, and a second input/output node, the switching device operative to pass or block the bidirectional transmission of external data signals between the first node and the second node, the switching device comprising a bidirectional field-effect transistor; a first scan cell; and a second scan cell; whereby input and output data signals of the switching device may be sensed and stored.
Claims10
A scan test device comprising:
- a bidirectional field-effect transistor including a first input/output terminal and a second input/output terminal and a gate terminal, said first input/output terminal being connected to a first node forming a first data path and said second input/output terminal being connected to a second node forming a second data path, such that said bidirectional field-effect transistor passes bidirectional external data signals between said first and second nodes when said bidirectional field-effect transistor is turned on and blocks the passage of external data signals between said first and second nodes when said bidirectional field-effect transistor is turned off;
- wherein said bidirectional field-effect transistor has a channel length of no more than 1.5 microns and has a channel width of no less than 1000 microns, such that said bidirectional field-effect transistor exhibits a time constant of no more than 5 nanoseconds;
- a driver circuit for providing an on/off control signal to said gate terminal of said bidirectional field-effect transistor;
- and
- first scan cell means operatively connectable to said first data path and operative to sense or store data signals from said first data path;
- second scan cell means operatively connectable to said second data path and operative to sense or store data signals from said second data path.
3 more elements
A scan test device comprising:
- multiple respective field-effect transistors, each including a respective first input/output terminal and a respective second input/output terminal and a respective gate terminal, each respective first input/output terminal being connected to a respective first input/output node forming a respective first data path and each respective second input/output terminal being connected to a respective second input/output node and forming a respective second data path, such that each respective field-effect transistor respectively passes bidirectional individual external data signals between respective individual first and second input/output nodes when said respective field-effect transistor is turned on and respectively blocks the passage of individual external data signals between respective individual first and second input/output nodes when said respective field-effect transistor is turned off;
- wherein each respective field-effect transistor has a channel length of no more than 1.5 microns and has a channel width of no less than 1000 microns such that each respective field-effect transistor exhibits a time constant of no more than 5 nanoseconds;
- and
- at least one driver circuit including a respective external terminal for receiving the at least one respective external on/off signal;
- wherein the at least one driver circuit provides a respective internal on/off control signal to respective control terminals of at least two of said respective field-effect transistors;
- and
- multiple respective first scan cell means, there being at least one first scan cell means connected to each respective first data path and operative to sense and store data signals from each respective first data path, and multiple respective second scan cell means, there being at least one scan cell means connected to each respective second data path and operative to sense and store data signals from each respective second data path.
4 more elements
Dependencies are inferred from the claim text.