The M27C4002 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 262,144 words of 16 bits. The FDIP40W (window ceramic frit-seal package) and the JLCC44W (J-lead chip carrier packages) have transparent lids 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 M27C4002 is offered in PDIP40, PLCC44 and TSOP40 (10 x 20 mm) packages.