| 摘要 |
<p>PURPOSE:To accurately detect a threshold voltage and to heighten reliability by equipping the title device with a buffer circuit with an external terminal as an input signal terminal and connecting the electrode of an MIS type nonvolatile memory transistor to the output part of the buffer circuit. CONSTITUTION:The title device is equipped with the buffer circuit having the external terminal as the input signal terminal, any one out of the gate electrode, the drain electrode, the source electrode, and the substrate electrode of an MIS type nonvolatile memory transistor Q6 is connected to an output part OUT1 of the buffer circuit, and the buffer circuit is equipped with a function to interrupt a high-voltage input signal. Memory data in the MIS type nonvolatile memory transistor Q6 are never changed even when a high-voltage pulse such as a static discharge is inputted through the external terminal, and the threshold voltage of the MIS type nonvolatile memory transistor can be accurately detected by fluctuating an external input terminal VM1 for detecting the threshold voltage. Thus, the reliability can be heightened.</p> |
