| 摘要 |
A period measuring device and a semiconductor memory device having the same are provided to rapidly measure the period of a signal related to the operation of the semiconductor memory device by converting the period into a digital signal. A period measuring device includes a period generating circuit(100), an input buffer(200), a period measuring circuit(300), and an output buffer(400). The period generating circuit provides a period signal, which is related to the period of a predetermined operation. The input buffer supplies an internal reference clock in a test mode. The period measuring circuit divides the internal reference clock, while the period signal is enabled in the test mode, generates clock division signals, latches the divided clocks, and outputs the result as an n-bit digital latch signal. The output buffer buffers the n-bit digital latch signal in the test mode and outputs the result as an n-bit output signal.
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