IDT72281/72291
CMOS SuperSync FIFO™ 65,536 x 9 and 131,072 x 9
COMMERCIALANDINDUSTRIAL
TEMPERATURERANGES
operation,whichconsistsofactivatingRENandenablingarisingRCLKedge,
willshiftthewordfrominternalmemorytothedataoutputlines.
DESCRIPTION(CONTINUED)
InFWFTmode,thefirstwordwrittentoanemptyFIFOisclockeddirectlyto
thedataoutputlinesafter threetransitionsoftheRCLKsignal.ARENdoesnot
havetobeassertedforaccessingthefirstword.However,subsequentwords
writtentotheFIFOdorequireaLOWonRENforaccess. ThestateoftheFWFT/
SIinputduringMasterResetdeterminesthetimingmodeinuse.
ForapplicationsrequiringmoredatastoragecapacitythanasingleFIFOcan
provide,theFWFTtimingmodepermitsdepthexpansionbychainingFIFOs
inseries(i.e.thedataoutputsofoneFIFOareconnectedtothecorresponding
data inputs of the next). No external logic is required.
TheinputportiscontrolledbyaWriteClock(WCLK)inputandaWriteEnable
(WEN)input. DataiswrittenintotheFIFOoneveryrisingedgeofWCLKwhen
WENisasserted.TheoutputportiscontrolledbyaReadClock(RCLK)input
andReadEnable(REN)input. DataisreadfromtheFIFOoneveryrisingedge
ofRCLKwhenRENisasserted. AnOutputEnable(OE)inputisprovidedfor
three-statecontroloftheoutputs.
ThefrequenciesofboththeRCLKandtheWCLKsignalsmayvaryfrom0
tofMAXwithcompleteindependence. Therearenorestrictionsonthefrequency
oftheoneclockinputwithrespecttotheother.
TheseFIFOshavefiveflagpins,EF/OR(EmptyFlagorOutputReady),FF/
IR(FullFlagorInputReady),HF(Half-fullFlag),PAE(ProgrammableAlmost-
Emptyflag)andPAF(ProgrammableAlmost-Fullflag). TheEFandFFfunctions
areselectedinIDTStandardmode. TheIRandORfunctionsareselectedin
Therearetwopossibletimingmodesofoperationwiththesedevices:IDT
Standard mode and First Word Fall Through (FWFT) mode.
InIDTStandardmode,thefirstwordwrittentoanemptyFIFOwillnotappear
onthedataoutputlinesunlessaspecificreadoperationisperformed.Aread
PINCONFIGURATIONS
PIN 1
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
WEN
SEN
DC(1)
1
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
DNC(3)
DNC(3)
GND
DNC(3)
DNC(3)
2
3
VCC
4
VCC
5
GND(2)
GND(2)
GND(2)
GND(2)
GND(2)
GND(2)
GND(2)
GND(2)
GND(2)
D8
6
VCC
DNC(3)
DNC(3)
DNC(3)
GND
DNC(3)
DNC(3)
Q8
7
8
9
10
11
12
13
14
15
16
Q7
Q6
D7
GND
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
4675 drw 02
TQFP (PN64-1, ORDER CODE: PF)
STQFP (PP64-1, ORDER CODE: TF)
TOP VIEW
NOTES:
1. DC = Don’t Care. Must be tied to GND or VCC, cannot be left open.
2. This pin may either be tied to GND or left open.
3. DNC = Do Not Connect.
2