AN620

www.DataSheet4U.com AN620 APPLICATION NOTE ON-BOARD PROGRAMMING OF OTP EPROM by Franco MORANDI In recent years interest has been growing in On-Board Programming of OTP EPROM memories. There are two main factors which have stimulated this interest: the growth of the FLASH Memory market and the increased use of surface mount packages. THE GROWTH OF THE FLASH MEMORY MARKET UV EPROMs and OTP EPROMs offer a higher degree of flexibility compared to Mask ROMs. This is due to their ability to be electrically programed and, in the case of the UV EPROM, erased by exposure to UV light, then re-programed. The ability to electrically program these parts is the most important feature which allows UV EPROMs or OTP EPROMs to be seen by users as ROMs which are programmable at the final moment in the exact quantity required. Programming of the memories is mainly done by the use of dedicated programing equipment using software algorithms which match those specified by the major chip makers. Fast programming services are also offered by testing houses and by vendors themselves for a small price premium. The plastic packaged OTP EPROMs are therefore regarded by many as ’flexible ROMs’. Programming of OTP EPROMs in the application board itself, rather than in the dedicated programming equipment, has not been common until the recent introduction of FLASH Memories. One of the important features of the FLASH Memory is its programability (and erase and re-programability) on board, in the application...