The M27C4001 is a 4 Mbit EPROM offered in the two ranges UV (ultra violet erase) and OTP (one time programmable). It is ideally suited for microprocessor systems requiring large programs and is organised as 524,288 by 8 bits. The FDIP32W (window ceramic frit-seal package) and LCCC32W (leadless chip carrier package) have a transparent lid which allow the user to expose the chip to ultraviolet light to erase the bit pattern. A new pattern can then be written to the device by following the programming procedure. For applications where the content is programmed only one time and erasure is not required, the M27C4001 is offered in PDIP32, PLCC32 and TSOP32 (8 x 20 mm) packages.