| 摘要 |
<p>The conductive state of a transistor in a semiconductor integrated circuit (10) is determined by irradiating the transistor with a radiation beam and measuring changes in load current, thereby indicating whether the transistor was conducting or non-conducting prior to irradiation. A correlated double sampling method is employed in measuring changes in load current. A load resistor (42) in series with the device under test is capacitively coupled to differential amplification means (46) including a plurality of differential amplifiers with buffers connected between successive amplifiers. A system clock (44) is stopped at a predetermined time period prior to irradiating the transistor. A bypass switch (43) shunts the load resistor (42) until the clock (44) is stopped.</p> |
