Reducing tester channels for high pinout integrated circuits

• US 6,971,045 B1
• Filed: 05/20/2002
• Issued: 11/29/2005
• Est. Priority Date: 05/20/2002
• Status: Active Grant

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Deb, Biswa M., Gupta, Rajat
• Primary Examiner(s): Beausoliel, Robert
• Assistant Examiner(s): Chu, Gabriel L.
• Application Number:
  US10/151,669
• Time in Patent Office: 1,289 Days
• Field of Search: 714/27, 714/30
• US Class Current: 714/30
• CPC Class Codes: G01R 31/3172 Optimisation aspects, e.g. using functional pin as test pin, pin multiplexing
• CPC Class Codes: G01R 31/31926 Routing signals to or from the device under test [DUT], e.g. switch matrix, pin multiplexing
• CPC Class Codes: G01R 31/31928 Formatter driver, receiver details G01R31/31924
• CPC Class Codes: G06F 11/263 Generation of test inputs, e.g. test vectors, patterns or sequences ; with adaptation of the tested hardware for testability with external testers

Abstract

An integrated circuit generally comprising a plurality of input pads, an input circuit, and a core circuit. The input pads may be configured to receive a plurality of first input signals. The input circuit may be configured to generate a plurality of second input signals (i) equal to the first input signals while in an operational mode and (ii) responsive to a plurality of test vectors with timing generation determined by the first signals while in a test mode. The core circuit may be responsive to the second input signals.

Claims

1. An integrated circuit comprising:

a plurality of input pads configured to receive a plurality of first input signals;

an input circuit configured to generate a plurality of second input signals (i) equal to said first input signals while in an operational mode and (ii) responsive to a plurality of test vectors with timing generation determined by said first input signals while in a test mode, wherein said input circuit comprises a data formatter configured to generate said second input signals in response to said first input signals and a plurality of test signals conveying said test vectors; and

a core circuit configured to (i) directly receive said second input signals and (ii) respond to said second input signals.

2. The integrated circuit according to claim 1, wherein said data formatter comprises a plurality of multiplexers addressed by said first input signals and said test signals.

3. The integrated circuit according to claim 2, wherein-said multiplexers are configurable to provide greater than four different logic functions.

4. The integrated circuit according to claim 3, wherein said multiplexers are configurable between (i) an AND function and (ii) a pass through function.

5. The integrated circuit according to claim 1, wherein said input circuit comprises a test vector generator configured to generate a plurality of test signals in response to a clock signal.

6. The integrated circuit according to claim 5, wherein said test vector generator comprises a memory configured to (i) store said test vectors and (ii) generate said test signals in response to said test vectors and an address signal.

7. The integrated circuit according to claim 6, wherein said test vector generator further comprises a counter configured to generate said address signal in response to said clock signal.

8. The integrated circuit according to claim 1, wherein said input circuit comprises a switching matrix configured to interconnect said input pads in response to a control signal.

9. The integrated circuit according to claim 8, wherein said input circuit further comprises a memory configured to (i) store said test vectors and (ii) generate said control signal in response to said test vectors.

10. The integrated circuit according to claim 1, further comprising:

an output circuit configured to (i) generate a plurality of second output signals equal to a plurality of first output signals generated by said core circuit while said output circuit has said operational mode and (ii) generate one of said second output signals in response to a comparison result of data in said first output signals to said test vectors while in said test mode; and

a plurality of output pads configured to directly receive said second output signals.

11. An integrated circuit comprising:

a core circuit configured to generate a plurality of first output signals;

an output circuit configured to (i) generate a plurality of second output signals equal to said first output signals while in an operational mode and (ii) generate one of said second output signals in place of one of said first output signals in response to a comparison result of data in said first output signals to a plurality of test vectors while in a test mode; and

a plurality of output pads configured to receive said second output signals.

12. The integrated circuit according to claim 11, wherein said output circuit comprises a comparison circuit configured to generate a status signal conveying said comparison result in response to comparing said first output signals to a plurality of test signals conveying said test vectors.

13. The integrated circuit according to claim 12, wherein said comparison circuit comprises a plurality of multiplexers configured to generate a plurality of intermediate signals in response to said first output signals and said test signals.

14. The integrated circuit according to claim 13, wherein said comparison circuit further comprises a logic gate configured to generate said status signal in response to said intermediate signals.

15. The integrated circuit according to claim 12, wherein said output circuit comprises a switching circuit configured to interconnect said output pads in response to a control signal.

16. The integrated circuit according to claim 15, wherein said output circuit further comprises a memory configured to (i) store said test vectors and (ii) generate said control signal in response to said test vectors.

17. The integrated circuit according to claim 11, wherein said output circuit comprises a multiplex circuit configured to generate said second output signals in response to said first output signals and a status signal conveying said comparison result.

18. The integrated circuit according to claim 17, wherein said multiplex circuit comprises a plurality of multiplexers configured to multiplex said first output signals and said status signal into said second output signals.

19. An integrated circuit comprising:

means for receiving a plurality of first input signals using a plurality of input pads;

means for generating a plurality of second input signals (i) equal to said first input signals while in an operational mode and (ii) responsive to a plurality of test vectors with timing generation of said second input signals determined by said first signals while in a test mode, wherein said means for generating a plurality of second input signals comprises a data formatter configured to generate said second input signals in response to said first input signals and a plurality of test signals conveying said test vectors; and

means responsive to said second input signals using a core circuit configured to directly receive said second input signals.