| 摘要 |
PURPOSE:To facilitate the screening of even a circuit block having no external terminal, by a method wherein a signal is applied from an input terminal to ascertain the continuity or non-continuity of an internal transistor (Tr) and with the confirmation thereof, a high voltage pulse is applied between power source terminals. CONSTITUTION:It is so arranged that the continuity or non-continuity of an NPN-Tr1 and PNP-Tr2 can be selected depending on the selection of a potential of an input terminal. When a high voltage pulse is applied to a high voltage side power source terminal (a) with the continuity of the Tr1 and the non- continuity of the Tr2, a high voltage works between the base/emitter line of the Tr1 and a low voltage side power source line and on the base line of the Tr2 and on a high voltage side power source line to allow the screening. Conversely, when with the non-continuity of the Tr1 and the continuity of the Tr2, a high voltage pulse is applied to the terminal (a), a high voltage works on the base line of the Tr1 and on the low voltage power source line and between the base/emitter line of the Tr2 and the high voltage power source line to allow the screening.
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