| 摘要 |
PURPOSE: A bonding option circuit is provided to be capable of utilizing all the select signals formed through combination of input conditions, thereby preventing the increase of unnecessary pads. CONSTITUTION: A voltage generator(302) generates VDD/2 voltage(VHVDD) corresponding to half of source voltage(VDD) and n channel bias voltage(VREFN)/ p channel bias voltage(VREFP). A bonding pad(304) is bonded to a power supply or a ground or is floated to generate a pad voltage. An n-channel voltage detector(306) generates an n-channel output voltage of high level if the pad voltage is input and the pad is connected to the power supply, generates the n-channel output voltage of low level if the pad is connected to the ground, and generates the n-channel output voltage of low level if the pad is floated. A p-channel voltage detector(308) generates a p-channel output voltage of high level if the pad voltage is input and the pad is connected to the power supply, generates the p-channel output voltage of low level if the pad is connected to the ground, and generates the p-channel output voltage of low level if the pad is floated. A mode output(310) generates a plurality of I/O structure select signals by combining the logic values of the n-channel output voltage and the p-channel output voltage.
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