Triaxial DC-AC connection system

Patent metadata

Field	Value
Publication number	US-9983228-B2
Application number	US-201514846121-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Sep 24, 2014
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

Embodiments of the present invention provide an improved two-cable connection system for connecting electrical test instrumentation to a device under test (DUT). In one embodiment, a single pair of equal-length triaxial cables each has a desired characteristic impedance. Each cable has a center connecter, intermediate conductor, and outer conductor. The proximal end of each cable is connected to the test instrumentation, and the distal ends are located at the DUT. At the distal end, the center conductors are connected to the DUT, the intermediate conductors are allowed to float, and the outer conductors are connected to each other. The proximal end of each cable is connected to the device using an appropriate connection for the test that will be performed. This allows the test instrumentation to perform different types of tests without changing connections to the DUT.

First claim

What is claimed is:

1. A system configured to perform at least two different types of tests on a device under test (DUT) without changing connections at the DUT, wherein a first type of test benefits from having a control impedance between a test instrument and the DUT and a second type of test does not benefit from having a control impedance between a test instrument and the DUT, the system comprising:
a test instrument;
a device under test (DUT); and
two or more triaxial cables with a distal end located near the DUT and a proximal end located near the test instrument, each cable having a center conductor, an intermediate conductor, and an outer conductor, wherein;
the center conductors are connected to the DUT at the distal end of each cable and to the test instrument at the proximal end of each cable;
the outer conductors are connected to each other at both the distal and proximal ends of the cables; and
the outer conductors are connected to a ground that is shared with the test instrument at the proximal ends of the cables; and

wherein the system is configured to perform the first type of test when the intermediate conductors are not connected to each other at the proximal ends of the cables and are not connected to the test instrument.

2. The system of claim 1 , wherein the test instrument comprises a first set of terminals and a second set of terminals that is different from the first set; and
the system is further configured to perform the first type of test when the cables are connected to the first set of terminals; and
the system is further configured to perform the second type of test when the cables are connected to the second set of terminals.

3. The system of claim 1 , wherein one or more of the intermediate conductors are further connected to an electrical signal or ground through an impedance that is at least ten times larger than the control impedance.

4. The system of claim 1 , wherein the ground is an internal ground of the instrument.

5. The system of claim 1 , wherein at least one of the outer conductor connections at the distal ends of the cables is made on a DUT carrier.

6. The system of claim 1 , wherein each cable has a desired characteristic impedance of 50 ohms between the center conductor and the outer conductor.

7. The system of claim 1 , wherein the test instrument requires that the cables have a matched impedance.

8. A system configured to perform at least two different types of tests on a device under test (DUT) without changing connections at the DUT, wherein a first type of test benefits from having a control impedance between a test instrument and the DUT and a second type of test does not, the system comprising:
a first test instrument for performing the first type of test;
a second test instrument for performing the second type of test;
a device under test (DUT); and
two or more triaxial cables with a distal end located near the DUT and a proximal end located near one of the test instruments, each cable having a center conductor, an intermediate conductor, and an outer conductor, wherein;
the center conductors are connected to the DUT at the distal end of each cable;
the outer conductors are connected to each other at both the distal and proximal ends of the cables; and
the outer conductors are connected to a ground that is shared with at least one of the test instruments at the proximal ends of the cables; and

wherein the system is configured to perform the first type of test when;
the center conductors are connected to the first test instrument at the proximal ends of the cables;
the intermediate conductors are not connected to each other at the proximal ends of the cables; and
the intermediate conductors are not connected to either of the first or second test instruments; and

wherein the system is configured to perform the second type of test when the center conductors are connected to the second test instrument at the proximal ends of the cables.

9. The system of claim 8 , wherein one or more of the intermediate conductors are further connected to an electrical signal or ground through an impedance that is at least ten times larger than the control impedance.

10. The system of claim 8 , wherein the ground is an internal ground of the first or second instrument.

11. The system of claim 8 , wherein at least one of the outer conductor connections at the distal ends of the cables is made on a DUT carrier.

12. The system of claim 8 , wherein each cable has a desired characteristic impedance of 50 ohms between the center conductor and the outer conductor.

13. The system of claim 8 , wherein at least one of the test instruments requires that the cables have a matched impedance.

Assignees

• Keithley Instruments

Inventors

• Goeke Wayne C
• Sobolewski Gregory

Classifications

• G01R31/18

  Subjecting similar articles in turn to test, e.g. go/no-go tests in mass production · CPC title

• G01R31/2607

  Circuits therefor (G01R31/2642 takes precedence) · CPC title

• G01R27/28

  Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems H04B3/46) · CPC title

• G01R31/2822

  of microwave or radiofrequency circuits (of attenuation, gain, e.g. using network analyzers G01R27/28) · CPC title

• G01R31/2889

  Interfaces, e.g. between probe and tester (G01R31/31905 and G01R1/07364 take precedence) · CPC title