memory products - Al Kossow's Bitsavers

MK4202(Q)-20WRITE CYCLE TIMINGElectrical Characteristics and Recommended AC Operating Conditions(0°C~TA~70"C) (Vcc = 5.0 ± 10%)STD ALTSYM SYM PARAMETER MINtAVAV tc Cycle Time 25tAvwL tAS Address Set-up Time to W LOW 0tWHAX tAH Address Hold Time from W HIGH 0tAVSL tAS Address Set-up Time to 5 LOW 0tSHAX tAH Address Hold Time from 5 HIGH 0tEVWL tES Chip Enable Set-up Time to W LOW 5tWHEX tEH Chip Enable Hold Time from W HIGH 0tEVSL IES Chip Enable Set-up Time to 5 LOW 5tSHEX tEH Chip Enable Hold Time to 5 HIGH 0tWLWH tww Write Pulse Width 15tSLSH tsw Chip Select Pulse Width 16tOVWH tos Data Set-up Time to W HIGH 10tWHOX tOH Data Hold Time from W HIGH 0tOVSH tos Data Set-up Time to S HIGH 10tSHOX tOH Data Hold Time from 5 HIGH 0tWLOZ twz Outputs Hi-Z from W LOWtwHOX tWL Outputs Low-Z from W HIGH 5MAX UNITS NOTESnsnsnsnsnsnsnsnsnsnsnsnsnsnsns8 nsnsCOMPARE MODEThe ~K4202 is in the Compare mode whenever Wand G are HIGH provided a true Chip Enablepattern (Eo-E3) is applied. Chip Select (5) is regardedas a don't care since the user is not concernedwith the data outputs....Q.ut only with the Compare(C,u outputs. Mx and Hx must be HIGH, and CGxactive LOW to enable the Compare outputs for avalid compare hit or miss.The 11 index address inputs (Ao-AlO) define aunique location in the static RAM array. The datapresented on the Data Inputs (00,-00'9 andCDOo) as Tag Data is compared to the internalRAM data as specified by the index. If all bits areequal (match) then a hit condition occurs(Cx = HIGH). If at .Ieast one bit is not equal, thena miss occurs (Cx = LOW).The Compare output will be valid tAVCV from stableaddress, or tovcv from valid tag data provided ChipEnable is true, and CGX is active LOW. Should theaddress be stable with valid tag data, and Chip Enablefalse, then compare access will be within tEVCVfrom true Chip Enable. When executing a write-tocomparecycle fiJ = LOW, and G = LOW or HIGH),Cx will be v~d tIQ/HCV or tGHCV from the latter risingedge of W or G respectively. Finally, whe~ingthe Cx output in the compare mode with CGx,the compare output will be valid tCGL-cv from thefalling edge of CGx.7118371