| 摘要 |
<p>PURPOSE:To prevent manufacturing processes from increasing in number by making use of ordinary-threshold-level MISFETs by using a write voltage signal as part of a memory-operation-mode discrimination signal and by utilizing variation in write voltage. CONSTITUTION:During write operation, a high voltage of 25V, for example, is applied to write voltage terminal Vpp, a pulse signal prescribing the write time is supplied to terminal PD/PGM, and write data are supplied to terminal I/O. During read operation, a low voltage of 5V is applied to terminal Vpp and a L-level signal is supplied to terminal PD/PGM. When the chip is unselected, terminal Vpp remains at 5V and a H-level signal is applied to terminal PD/PGM. Program pulse circuit 1 and power-down control circuit 2 supply a high voltage to decoders 3 and 4 at the time of writing to write information to nonvolatile memory Qc of a floating gate MISFET. At the time of reading, decoders 3 and 4 are activated by signal PDC of circuit 2 and FETQ42 is turned ON by signal PGM of circuit 1 to read the information of memory QC3 out. When the chip is unselected, decoders 3 and 4 are inactivated to reduce the power consumption.</p> |
