| 摘要 |
<p>PURPOSE:To realize guarantee test of a clock pulse width by constituting a ring oscillator of a clock distributing circuit and measuring the accurate quantity of variance in delay of the clock distributing circuit made of an IC. CONSTITUTION:A clock width determining circuit 41, a clock output circuit 42 which outputs the signal of OR between the signal of a clock width determining input pin 10 and that of a clock input pin 11 to clock output pins 21 and 22, and a pin 12 constituting the ring oscillator are provided. The ring oscillator is constituted on a test board at the time of testing the IC of the clock distributing circuit and its oscillation frequency is measured, thereby securing the clock pulse width. Since the ring oscillator is constituted and the oscillation frequency is measured in such a manner, the precision of a frequency measurer is high, and the quantity of variance among busses of the clock distributing circuit made of the IC is accurately measured.</p> |
