description the accutek ak536256w high density memory module is a cmos dynamic ram organized in 256k x 36 bit words. the module con - sists of eight standard 256 k x 4 drams in plastic soj packages and four 256k x 1 drams in plcc packages. the assembly has 12 drams mounted on the front side of a printed circuit board in a 72 pad leadless sim configuration. the operation of the ak536256w is identical to eight 256 k x 4 plus four 256 k x 1 drams. there are four cas lines and two ras lines. independent byte control is accomplished by four cas lines. each separate cas line controls two 256 k x 4 drams, along with one 256k x 1 dram with data in tied to data out to form a 9 bit byte. the bank of 36 bits is controlled by the two ras lines. an eighteen bit data path can be produced by connecting dq 0 to dq 18 ,dq 1 to dq 19 , etc. and alternately strobing ras 0 and ras 2 . features 262,144 x 36 bit organization 72 pad single in-line module multiple cas and ras lines allow x18 or x36 bit widths cas -before-ras refresh operating free air temperature 0 o cto70 o c single 5 volt power supply power 2.705 watt max active (70ns) 2.375 watt max active (80 ns) 2.045 watt max active (100 ns) 66 mw max standby 512 refresh cycles, 8 msec available in fast page mode and static column mode ver- sions upward compatible with ak536512w, AK5361024W, ak5362048w, ak5364096w and ak5368192w accutek microcircuit corporation ak536256w 262,144 word by 36 bit cmos dynamic random access memory + + pin nomenclature dq 0 -dq 35 data in/data out a 0 -a 8 address inputs cas 0 - cas 3 column address strobe ras 0, ras 2 row address strobe we write enable pd presence detect vcc 5v supply vss ground nc no connect module options leadless sim: ak536256w leaded zip: ak536256z pin assignment pin # symbol pin # symbol pin # symbol pin # symbol 1 vss 19 nc 37 dq17 55 dq12 2 dq0 20 dq4 38 dq35 56 dq30 3 dq18 21 dq22 39 vss 57 dq13 4 dq1 22 dq5 40 cas 0 58 dq31 5 dq19 23 dq23 41 cas 2 59 vcc 6 dq2 24 dq6 42 cas 3 60 dq32 7 dq20 25 dq24 43 cas 1 61 dq14 8 dq3 26 dq7 44 ras 0 62 dq33 9 dq21 27 dq25 45 nc 63 dq15 10 vcc 28 a7 46 nc 64 dq34 11 nc 29 nc 47 we 65 dq16 12 a0 30 vcc 48 nc 66 nc 13 a1 31 a8 49 dq9 67 pd1 14 a2 32 nc 50 dq27 68 pd2 15 a3 33 nc 51 dq10 69 pd3 16 a4 34 ras 2 52 dq28 70 pd4 17 a5 35 dq26 53 dq11 71 nc 18 a6 36 dq8 54 dq29 72 vss presence detect - -60 -70 -80 pd1 vss vss vss pd2 nc nc nc pd3 nc vss nc pd4 nc nc vss
functional diagram mechanical dimensions 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 e-mail: 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 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. c l c l c l + + 4.240" 4.260" 1.000" max 0.200" max 0.425" 0.375" 0.250" c l 0.080" 3.979" 3.989" 0.125" 0.050" typ a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 dq1 dq2 dq3 dq4 ras cas we oe a0 - a8 ras cas we a0 - a8 ras cas we a0 - a8 ras cas we a0 - a8 ras cas we d q d q d q d q dq0 dq1 dq2 dq3 dq18 dq19 dq20 dq21 dq9 dq10 dq11 dq12 dq27 dq28 dq29 dq30 dq4 dq5 dq6 dq7 dq22 dq23 dq24 dq25 dq13 dq14 dq15 dq16 dq31 dq32 dq33 dq34 dq8 dq26 dq17 dq35 cas ras 0 0 cas ras 2 2 cas1 cas3 a0 a1 a2 a3 a4 a5 a6 a7 a8 we
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