| 摘要 |
PURPOSE:To read a kind identification code even in the case of the EPROM built-in with a redundant cell especially, the having a kind identification code separately and incorporating a transfer for switching data with EPROM and a selection circuit. CONSTITUTION:A kind identification code built-in EPROM(erasable programmable read only memory) has a kind identification code 7 in addition to an internal circuit 1 and a high voltage detection circuit 2 and is equipped with transfer gates 5, 6 switching the internal circuit 1 and kind identification code 7 respectively and a selection circuit 8 selecting the transfer gates 5, 6 with the signal of the high voltage detection circuit 2. In case of reading the kind identification code, a high voltage is impressed on an Ag terminal, the high voltage detection circuit 2 detects the impression of the high voltage, the selection of the selection circuit 8 varies, the switching transfer 5 is cut off and the output of the internal circuit 1 is cut off. The switching transfer 6 is then selected vice versa, the data of the kind identification code 7 is passed through the transfer 6 and output from an output circuit 4. The kind identification code 7 can thus be read. |
