LSI having a built-in self-test circuit
AssigneeNEC Electronics Corporation
InventorYasuhiro Fukuda
Life of this patent
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Abstract
A LSI includes a logic circuit, a PLL circuit and a built-in self-test (BIST) circuit. When the PLL circuit detects a phase lock of the system clock signal of the LSI with a reference clock signal under the condition of presence of a test instruction signal, the PLL delivers a test enable signal to the BIST circuit. The BIST circuit responds to the test enable signal to test the logic circuit in a functional test. The BIST circuit transmits the test result data to an IC tester after the functional test. Throughput of the functional test can be improved by eliminating transmission of the test enable signal from the IC tester to the LSI.
Claims4
A large-scale integrated circuit (LSI) comprising:
- a phase-locked-loop (PLL) circuit for receiving a reference clock signal to generate a system clock signal, said PLL circuit comparing a phase of said system clock signal against a phase of said reference clock signal to detect a phase lock therebetween;
- a logic circuit for operating with said system clock signal for signal processing;
- and
- a built-in self-test (BIST) circuit for responding to a test enable signal to test the logic circuit in a functional self-test and receive test result data from said logic circuit;
- wherein said PLL circuit responds to a test instruction signal to generate said system clock signal and transmits said test enable signal to said BIST circuit upon detecting said phase lock under the presence of said test instruction signal.
Dependencies are inferred from the claim text.