memory products - Al Kossow's Bitsavers

ETC2716ERASING~he ETC?716 !s erased by exposure to high inten­Slt~ ultraviolet hght through the transparent window.:r~I~ exposure discharges the floating gate to itsmilial state through induced photo current. It is recomme~dedthat the ETC2716 be kept out of directs~nhght. The UV content of sunlight may causea p~rllal e.rasure. of some bits in a relatively shortpenod of time. Direct sunlight can also cause temporaryfunctional failure. Extended exposure toroom level fluorescent lighting will also cause erasure.An opaque coating (paint, tape, label,etc.)should ~e placed over the package window if thisp~?duct IS to ~e operated under these lighting condilions.Covenng the window also reduces ICC dueto photodiode currents.An ultraviolet source of 2537A yielding a total integrateddosage of 15 watt-seconds/cm 2 is requi-red. This will erase the partin approximately 15 to20 min~tes!f a UV lamp with a 12,000 /l-W/cm 2 powerratmg IS used. The ETC2716 to be erasedshould be place 1 inch away from the lamp and nofilters should be used.An erasu.re system should be calibrated periodically.The distance from lamp to unit should be maintainedat 1 inch. The erasure time is increased bythe square of the distance (if the distance is doubledthe erasure time goes up by a factor of 4).Lamps lose intensity as they age. When a lamp ischanged, the distance is changed, or the lamp isaged, the system should be checked to make certa.infull erasure is occurring. Incomplete erasurewill cause symptoms that can be misleading. Programmers,components, and system designs havebeen erroneously suspected when incompleteerasure was the basic problem.TIMING DIAGRAMPROGRAM MODEPROGRAM__ PROGRAM VERIFY(DE VIH) (DE VIL) .VIH~~~~------------~~------------~ADDRESSESVIL~~~~~~ __ ~~~~~~::~ ______ J ~~A_DD_R_E_S_S_X_+_1DATAVIL===~DATA IN STABLEADDRESS X + 1_GVIH------~--_1--tl--,t~D~H--t--r--~VIL tDS (TPLDX) -(TDVPH) -- -1(TGHPH)VIH ------------:.....j....jtE/P'VIL ~=====;;tjtpw_ tos ~ ~--- - (TPHPL)tPF(TPL 1 PL1)Note: Symbols in parentheses are proposed JEDEC standard6/996