| 摘要 |
PURPOSE:To distinguish products easily, and to eliminate trouble on a mass production by providing the inside of an IC with a mask discriminating means, a signal converting means converting an output from the discriminating means, a changeover means connecting an output from the signal converting means to an external terminal and a test circuit controlling the changeover means besides a functional circuit. CONSTITUTION:The inside of an IC is provided with a mask discriminating circuit 53, a signal converting circuit 25, a changeover circuit 21, and frequency dividing circuits 9-11 besides a functional circuit, and products are distinguished by these circuits at every renewal of mask blocks. Mask detecting switches 3-5 and resistors 6-8 are mounted into the circuit 25, and the circuit 25 is constituted by inverters 12 and 13, NOR circuits 15 and 16 and NAND circuits 17-20. Accordingly, the number of mask blocks can be made sure by a simple measuring instrument. |
