| 摘要 |
PROBLEM TO BE SOLVED: To provide a bidirectional interface circuit (bidirectional buffer circuit), which is provided with an output circuit that drives the output by means of an N-type MOS transistor only and an input circuit composed of a P-type MOS transistor and an N-type MOS transistor and on which IDDQ tests can be carried out effectively, by interrupting the propagation of intermediate-potential signals even when its outside output terminal incapable of swinging fully to its internal power supply voltage. SOLUTION: In an output mode, in which an enable signal EN is set at 'H' level, an output data signal D in the preceding stage of an output circuit 10 is supplied to an input section 21, by setting one buffer gate 25 in an input selector section 23 to a conducted state. The supply of an intermediate-potential signal outputted to an outside output terminal 101 via an output drive section 12 to the input section 21 is inhibited by setting the other buffer gate 24 in a non-conducted state.
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