description the accutek AK632256W-72 sram module consists of fast high performance srams mounted on a low profile, 72 pin sim board. the module utilizes four 28 pin 256 k x 4 srams in 400 mil soj packages and four decoupling capacitors mounted on each side of a printed circuit board. the srams used have common i/o functions and single output en - able functions. also, four separate chip select (ce ) connections are used to independently enable the four bytes. the modules can be supplied in a variety of access time values from 12 nsec to 45 nsec in cmos or bicmos technology. the accutek module is designed to have a maximum seated height of 0.680 inch to provide for the lowest height off the board. by off - set-mounting the back surface srams the module can be mounted in either angled or straight-up sim sockets. the module conforms to jedec standard sizes and pin-out configurations. using four pins for module memory density identification, pd 0 to pd 3 , mini - mizes interchangeability and design considerations when changing from one module size to another in customer applications. features 262,144 x 32 bit organization jedec standardized 72 pin sim or zip pinout common i/o, single oe functions with four separate chip se- lects (ce ) low height, 0.680 inch maximum upward compatible with 512k x 32 (ak632512) and 1 meg x 32 (ak6321024) downward compatible with 32k x 32 (ak63232), 64k x 32 (ak63264) and 128k x 32 ak632128 presence detect pd 0 to pd 3 for identifying module density fast access times range from 12 nsec bicmos to 45 nsec cmos ttl-compatible inputs and outputs single 5 volt power supply - AK632256W-72 single 3.3 volt power supply - AK632256W-72/3.3 operating temperature range in free air, 0 0 cto70 0 c electrical specifications timing diagrams and basic electrical characteristics are those of the standard 256k x 4 srams used to construct these modules. accutek?s module design allows the flexibility of selecting indus- try-compatible 256k x 4 srams from several semiconductor manu - facturers. accutek microcircuit corporation AK632256W-72 262,144 x 32 bit cmos/bicmos 72 pin format static random access memory front view 72-pin sim pin nomenclature a 0 -a 17 address inputs ce 1 -ce 4 chip enable dq 1 -dq 32 data in/data out oe output enable pd 0 -pd 3 presence detect vcc 5v supply vss ground we write enable nc no connect module options leadless sim: AK632256W-72 pin assignment pin # symbol pin # symbol pin # symbol pin # symbol 1nc19a137ce 455 a5 2nc20a838ce 3 56 a12 3 pd2/nc 21 a2 39 a17 57 vcc 4 pd3/nc 22 a9 40 a16 58 a13 5 vss 23 dq13 41 oe 59 a6 6 pd0 24 dq5 42 vss 60 dq21 7 pd1 25 dq14 43 dq25 61 dq29 8 dq1 26 dq6 44 dq17 62 dq22 9 dq9 27 dq15 45 dq26 63 dq38 10 dq2 28 dq7 46 dq18 64 dq23 11 dq10 29 dq16 47 dq27 65 dq31 12 dq3 30 dq8 48 dq19 66 dq24 13 dq11 31 vss 49 dq28 67 dq32 14 dq4 32 we 50 dq20 68 vss 15 dq12 33 a15 51 a3 69 a18/nc 16 vcc 34 a14 52 a10 70 a19/nc 17 a0 35 ce 253 a4 71 nc 18 a7 36 ce 1 54 a11 72 nc pd0 = vss pd2 = open pd1 = vss pd3 = open 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 the numbers and coding on this page do not include all varia - tions available but are shown as examples of the most widely used variations. contact accutek if other information is re - quired. 0.350 max 0.680 0.670 4.245 4.255 0.475 0.425 c l 0.240 0.260 0.050 typ c l c l 0.130 0.120 1 3.995 3.975 0.400 0.680 0.670 0.080 0.070 accutek microcircuit corporation business center at newburyport 2 new pasture road, suite 1 newburyport, ma 01950-4054 phone: 978-465-6200 fax: 978-462-3396 email: sales@accutekmicro.com internet: www.accutekmicro.com examples: ak632256w72-12 256k x 32, 12 nsec sram module, 72 pin sim configuration accutek reserves the right to make changes in specifications at any time and without notice. accutek does not assume any responsibility for the use of any circuitry described; no circuit patent licenses are implied. preliminary data sheets contain minimum and maximum limits based upon design objectives, which are subject to change upon full characterization over the specific operating conditions. mechanical dimensions inches
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