| 摘要 |
PURPOSE:To simply read out a ROM code number by providing a code circuit having a second transistor for forming one bit of the code number according to the presence or absence of a depletion ion implantation and a third transistor connected in series with the second transistor in parallel with a first transistor for pulling up or down the input terminal of an inner input circuit. CONSTITUTION:In P-type first transistors Q11-Q1n, drains are connected to the input terminals of inner input circuits B1B2, gates are grounded, and the input terminals are pulled up. In code circuits A11-A1n, an N-type second transistor Q21 for forming one bit of a ROM code number for identifying a product according to the presence or absence of a depletion ion implantation and a P-type third transistor Q31 connected in series with the second transistor are provided, connected in parallel with the transistors Q11-Q1n, and the gates of the transistors Q21-Q2n, Q31-Q3n are grounded. Then, the input terminal of the inner input circuit is pulled up together with the transistors Q11-Q1n. |
