Semiconductor device for accurate measurement of time parameters in operation

摘要

A memory-logics LSI device forms an input/output path for testing. A memory device has a memory input/output unit, which includes an input/output selector with test function. A test clock signal, TCLK, directly supplied in the test mode, is used to selectively take in one of input signals DIk:0, COMi:0 and ADDm:0 and an output signal DOk:0 to output the signal so taken in. This output is monitored on an external pin, while changing the timing of the positive-going edge of the clock signal, CLK, or the input signals DIk:0, COMi:0 and ADDm:0. Relative measurement is then made on a delay amount indicating to which extent the input signals are delayed to cause a phase shift with respect to the clock signal, TCLK, at the timing immediately before input to and after output from the memory device.