An OTP test circuit on the 4Mb CMOS EPROM

Recently, in the field of the nonvolatile memories, the demand for OTP-ROM (One Time Programmable-ROM) devices has been rapidly increasing. The OTP-ROM is an EPROM enclosed in a plastic package. From the market research, EPROMs are programmed only once in many cases. If an EPROM is enclosed in a more inexpensive plastic package rather than a package with a window for UV (Ultra-Violet) erasure, it could become cheaper and more competitive with a MASK-ROM device in cost Moreover, it is more attractive for the users to get the ROM programmed as they want, in shorter time.