IDT7203/7204/7205/7206/7207/7208CMOSASYNCHRONOUSFIFO
2,048 x 9, 4,096 x 9, 8,192 x 9, 16,384 x 9, 32,768 x 9, 65,536 x 9
COMMERCIAL,INDUSTRIALANDMILITARY
TEMPERATURERANGES
W
R
tWHF
tRHF
HALF-FULL OR LESS
HF
HALF-FULL OR LESS
MORE THAN HALF-FULL
2661 drw11
Figure 9. Half-Full Flag Timing
WRITE TO
LAST PHYSICAL
LOCATION
W
R
READ FROM
LAST PHYSICAL
LOCATION
tXOL
tXOH
tXOL
tXOH
XO
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Figure 10. Expansion Out
tXI
tXIR
XI
tXIS
WRITE TO
FIRST PHYSICAL
LOCATION
W
R
tXIS
READ FROM
FIRST PHYSICAL
LOCATION
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Figure 11. Expansion In
7204/7205/7206/7207/7208s. ThesedevicesoperateintheDepthExpansion
modewhenthefollowingconditionsaremet:
OPERATINGMODES:
Care must be taken to assure that the appropriate flag is monitored by
eachsystem(i.e.FFismonitoredonthedevicewhereWisused;EFismonitored
onthedevicewhereRisused).ForadditionalinformationontheIDT7203/7204/
7205/7206/7207, refer to Tech Note 8: Operating FIFOs on Full and Empty
Boundary Conditions and Tech Note 6: Designing with FIFOs.
Single Device Mode
1. ThefirstdevicemustbedesignatedbygroundingtheFirstLoad(FL)control
input.
2. Allotherdevices musthave FLinthe HIGHstate.
3. TheExpansionOut(XO)pinofeachdevicemustbetiedtotheExpansion
In (XI) pin of the next device. See Figure 14.
4. ExternallogicisneededtogenerateacompositeFullFlag(FF)andEmpty
Flag(EF). This requires theORingofallEFs andORingofallFFs (i.e.all
mustbesettogeneratethecorrectcomposite FForEF). SeeFigure14.
5. TheRetransmit(RT)functionandHalf-FullFlag(HF)arenotavailablein
theDepthExpansionMode.
A single IDT7203/7204/7205/7206/7207/7208 may be used when the
applicationrequirementsarefor2,048/4,096/8,192/16,384/32,768/65,536words
orless. These FIFOs are ina Single Device Configurationwhenthe Expansion
In (XI) control input is grounded (see Figure 12).
Depth Expansion
These FIFOs can easily be adapted to applications when the require-
mentsareforgreaterthan2,048/4,096/8,192/16,384/32,768/65,536words.
Figure14demonstratesDepthExpansionusingthreeIDT7203/7204/7205/
7206/7207/7208s. AnydepthcanbeattainedbyaddingadditionalIDT7203/
For additional information on the IDT7203/7204/7205/7206/7207, refer to
Tech Note 9: Cascading FIFOs or FIFO Modules.
9
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
