| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrostatic protective circuit 100 for positively applying a surge current due to electrostatic discharge (ESD) applied to an output pad Vout to a low-potential line Vss without depending on the number of bits of an input/output signal, and a semiconductor device including the electrostatic protective circuit 100. SOLUTION: Even if the number of bits of an input/output signal is the theoretical maximum value, i. e. 1, a thyristor operation guaranteeing circuit 120 including a first capacitive element C1 connected between a high-potential line Vdd and a low potential line Vss always guarantees a constant sufficient capacity without depending on the number of bits of the input/output signal. Thus, the surge current due to the electrostatic discharge (ESD) applied to the output pad Vout is input into the first capacitive element C1, and the element C1 is changed. Accordingly, using a current based on the surge current, a thyristor rectifying current 110 starts a thrysistor operation. In this way, since the surge current flows to the low-potential line Vss via the thyristor rectifying circuit 110, a CMOS inverter 300 as an internal circuit to be protected is effectively protected from the surge current. COPYRIGHT: (C)2007,JPO&INPIT
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