| 摘要 |
<p>An objective of the present invention is to provide a ring oscillator which is capable of separately measuring the rise delay time and the fall delay time of a device constituting an SRAM cell. A ring oscillator (3) includes a plurality of delay circuits to be ring-connected, wherein at least one of the delay circuits includes a delay element (12, 16) formed in a layout region including the same layout shape as the layout shape of an SRAM cell, and a path circuit (20) connected in parallel to the delay element (12, 16). The delay element (12, 16) outputs an output signal to a delay circuit in the next stage within the delay circuits in response to one of rise transition and fall transition of a signal input to the input terminal of the delay element from a delay circuit in the previous stage within the delay circuits. The path circuit (20) outputs an output signal to the delay circuit in the next stage in response to the transition other than the one transition.</p> |
