description the accutek ak49256 high density memory modules is a random access memory organized in 256k x 9 bit words. the assembly consists of nine standard 256k x 1 drams in plastic leaded chip carriers (plcc) mounted on the front side of a printed circuit board. the module can be configured as a leadless 30 pad sim or a leaded 30 pin sip. this packaging approach provides a 6 to 1 density in - crease over standard dip packaging. the operation of the ak49256 is identical to nine 256k x 1 drams. for the lower eight bits data input is tied to the data output and brought out separately for each device, with common ras and cas control. this common i/o feature dictates the use of early-write cy - cles to prevent contention of d and q. since the write-enable (we ) signal must always go low before cas in a write cycle, read-write and read-modify-write operation is not possible. for the ninth bit, the data input (d 9 ) and the data output (q 9 ) pins are brought out separately and controlled by a separate pcas for that bit. bit nine is generally used for parity. features 262,144 by 9 bit organization optional 30 pad leadless sim (single in-line module) or 30 pin leaded sip (single in-line package) jedec standard pinout common cas and ras control for the lower eight bits separate pcas control for d 9 and q 9 3.15 watt active and 205 mw standby (max) operating free air temperature 0 0 cto70 0 c upward compatible with ak491024, ak591024, ak594096 and ak5916384 functionally and pin compatible with ak59256a accutek microcircuit corporation AK49256S / ak49256g 262,144 word by 9 bit mos dynamic random access memory 1 30 1 front view 30-pin sim 30-pin sip pin nomenclature a 0 -a 8 address inputs dq 1 -dq 8 data in / data out d 9 data in 9 q 9 data out 9 cas , pcas column address strobe ras row address strobe we write enable vcc 5v supply vss ground nc no connect module options leadless sim: AK49256S leaded sip: ak49256g pin assignment pin # symbol pin # symbol 1 vcc 16 dq5 2 cas 17 a8 3 dq! 18 nc 4a019nc 5 a1 20 dq6 6 dq2 21 we 7 a2 22 vss 8 a3 23 dq7 9 vss 24 nc 10 dq3 25 dq8 11 a4 26 q9 12 a5 27 ras 13 dq4 28 pcas 14 a6 29 d9 15 a7 30 vcc functional diagram
ordering information part number coding interpretation position 12345678 1 product ak = accutek memory 2 type 4 = dynamic ram 5 = cmos dynamic ram 6 = static ram 3 organization/word width 1 = by 1 16 = by 16 4 = by 4 32 = by 32 8 = by 8 36 = by 36 9 = by 9 4 size/bits depth 64 = 64k 4096 = 4 meg 256 = 256k 8192 = 8 meg 1024 = 1 meg 16384 = 16 meg 5 package type g = single in-line package (sip) s = single in-line module (sim) d = dual in-line package (dip) w = .050 inch pitch edge connect z = zig-zag in-line package (zip) 6 special designation p = page mode n = nibble mode k = static column mode w = write per bit mode v = video ram 7 separator - = commercial 0 0 cto+70 0 c m = military equivalent screened (-55 0 c to +125 0 c) i = industrial temperature tested (-45 0 cto+85 0 c) x = burned in 8 speed (first two significant digits) drams srams 50 = 50 ns 8 = 8 ns 60 = 60 ns 10 = 10 ns 70 = 70 ns 12 = 12 ns 80 = 80 ns 15 = 15 ns 1 30 3.525 3.475 0.100 typ 0.325 0.275 0.100 t. p. 3.100 3.090 0.024 0.016 0.425 0..375 .100 .060 0.685 0.635 1 0.685 0.635 0.100 typ 0.100 typ 0.200" max 0.053 0.047 accutek microcircuit corporation 5 new pasture road newburyport, ma 01950-4040 phone: 978-465-6200 fax: 978-462-3396 email: sales@accutekmicro.com internet: www.accutekmicro.com accutek reserves the right to make changes in specifications at any time and without notice. accutek does not assume any responsibil - ity for the use of any circuitry described; no circuit patent licenses are implied. preliminary data sheets contain minimum and maxi - mum limits based upon design objectives, which are subject to change upon full characterization over the specific operating condi - tions. mechanical dimensions inches the numbers and coding on this page do not include all variations avail - able but are show as examples of the most widely used variations. contact accutek if other information is required. examples: AK49256Sp-10 256k x 9, 100 nsec dram 30 pin sim configuration, page mode ak49256gk-80 256k x 9, 80 nsec dram 30 pin sip confi guration, static column mode
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