72V3622L15PQF [IDT]

PQFP-132, Tray;
72V3622L15PQF
型号: 72V3622L15PQF
厂家: INTEGRATED DEVICE TECHNOLOGY    INTEGRATED DEVICE TECHNOLOGY
描述:

PQFP-132, Tray

文件: 总29页 (文件大小:430K)
中文:  中文翻译
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3.3 VOLT CMOS SyncBiFIFOTM  
256 x 36 x 2  
512 x 36 x 2  
IDT72V3622  
IDT72V3632  
IDT72V3642  
1,024 x 36 x 2  
FFA/IRA, EFA/ORA, AEA, and AFA flags synchronized by CLKA  
FFB/IRB, EFB/ORB, AEB, and AFB flags synchronized by CLKB  
Select IDT Standard timing (using EFA, EFB, FFA and FFB flags  
functions) or First Word Fall Through timing (using ORA, ORB, IRA  
and IRB flag functions)  
FEATURES:  
Memory storage capacity:  
IDT72V3622  
IDT72V3632  
IDT72V3642  
256 x 36 x 2  
512 x 36 x 2  
1,024 x 36 x 2  
Available space-saving 120-pin Thin Quad Flatpack (TQFP)  
Functionally compatible to the 5V operating IDT723622/723632/  
723642  
Supports clock frequencies up to 100 MHz  
Fast access times of 6.5ns  
Free-running CLKA and CLKB may be asynchronous or coincident  
(simultaneous reading and writing of data on a single clock edge  
is permitted)  
Industrial temperature range (–40οC to +85οC) is available  
Green parts available, see ordering information  
Two independent clocked FIFOs buffering data in opposite direc-  
tions  
Mailbox bypass register for each FIFO  
Programmable Almost-Full and Almost-Empty flags  
Microprocessor Interface Control Logic  
DESCRIPTION:  
TheIDT72V3622/72V3632/72V3642arefunctionallycompatibleversions  
of the IDT723622/723632/723642, designed to run off a 3.3V supply for  
exceptionallylow-powerconsumption. Thesedevicesaremonolithic, high-  
FUNCTIONAL BLOCK DIAGRAM  
MBF1  
Mail 1  
Register  
CLKA  
CSA  
Port-A  
Control  
Logic  
W/RA  
RAM  
ENA  
ARRAY  
MBA  
256 x 36  
512 x 36  
1,024 x 36  
36  
FIFO1,  
Mail1  
Reset  
Logic  
RST1  
Write  
Pointer  
Read  
Pointer  
36  
Status Flag  
Logic  
EFB/ORB  
AEB  
FFA/IRA  
AFA  
FIFO 1  
FS  
0
1
Programmable Flag  
Offset Registers  
Timing  
Mode  
FWFT  
FS  
A
0
- A35  
10  
B0 - B35  
FIFO 2  
Status Flag  
EFA/ORA  
FFB/IRB  
AFB  
Logic  
AEA  
36  
Read  
Pointer  
Write  
Pointer  
36  
FIFO2,  
Mail2  
Reset  
Logic  
RST2  
RAM  
ARRAY  
256 x 36  
512 x 36  
CLKB  
CSB  
W/RB  
Port-B  
Control  
Logic  
1,024 x 36  
ENB  
Mail 2  
Register  
MBB  
4660 drw 01  
MBF2  
CIDTOandMtheMIDTElogRoaCrereIgAisteLredtrTadeEmaMrkoPfInEtegRrateAdDTevUiceTRecEhnologRy,IAnc NSynGcBiEFIFOisatrademarkofIntegratedDeviceTechnology,Inc.  
MAY 2013  
1
©
2013 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.  
DSC-4660/8  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
These devices are a synchronous (clocked) FIFO, meaning each port  
employsasynchronousinterface.Alldatatransfersthroughaportaregated  
totheLOW-to-HIGHtransitionofaportclockbyenablesignals.Theclocksfor  
each port are independent of one another and can be asynchronous or  
coincident. The enables for each port are arranged to provide a simple  
bidirectionalinterfacebetweenmicroprocessorsand/orbuseswithsynchro-  
nouscontrol.  
DESCRIPTION(CONTINUED)  
speed,low-power,CMOSBidirectionalSyncFIFO(clocked)memorieswhich  
supportclockfrequenciesupto100MHzandhavereadaccesstimesasfast  
as 6.5ns. Two independent 256/512/1,024 x 36 dual-port SRAM FIFOs on  
boardeachchipbufferdatainoppositedirections.Communicationbetween  
eachportmaybypasstheFIFOsviatwo36-bitmailboxregisters.Eachmailbox  
register has a flag to signal when new mail has been stored.  
PIN CONFIGURATION  
B
B
B
B
35  
34  
33  
32  
90  
89  
88  
87  
86  
85  
84  
83  
82  
81  
80  
79  
78  
77  
76  
75  
74  
73  
72  
71  
70  
69  
68  
67  
66  
65  
64  
63  
62  
61  
A
A
A
A
35  
34  
33  
32  
1
2
3
4
GND  
V
CC  
5
B
B
B
B
B
B
V
B
B
31  
30  
29  
28  
27  
26  
CC  
25  
24  
A
31  
6
A30  
7
GND  
8
A
A
A
A
A
A
A
29  
28  
27  
26  
25  
24  
23  
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
28  
29  
30  
GND  
B
B
B
B
B
B
23  
22  
21  
20  
19  
18  
FWFT  
A
22  
CC  
V
A
21  
20  
19  
18  
A
A
A
GND  
B
B
V
B
B
B
B
17  
16  
CC  
15  
14  
13  
12  
GND  
A
A
A
A
A
17  
16  
15  
14  
13  
V
CC  
GND  
A12  
4660 drw 03  
TQFP (PN120-1, order code: PF)  
TOP VIEW  
2
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
aselectednumberofwordsremainintheFIFOmemory. AFAandAFBindicate  
when the FIFO contains more than a selected number of words.  
FFA/IRA,FFB/IRB,AFAandAFBaretwo-stagesynchronizedtotheport  
clockthatwritesdataintoitsarray. EFA/ORA, EFB/ORB, AEA andAEB are  
two-stage synchronized to the port clock that reads data from its array.  
ProgrammableoffsetsforAEA,AEB,AFAandAFBareloaded byusingPort  
A.Threedefaultoffsetsettingsarealsoprovided.TheAEAandAEBthreshold  
canbesetat8,16or64locationsfromtheemptyboundaryandtheAFAand  
AFBthresholdcanbesetat8,16or64locationsfromthefullboundary.Allthese  
choices are made using the FS0 and FS1 inputs during Reset.  
Twoormoredevicesmaybeusedinparalleltocreatewiderdatapaths.  
If, at any time, the FIFO is not actively performing a function, the chip will  
automatically power down. During the power down state, supply current  
consumption(ICC)isataminimum.Initiatinganyoperation(byactivatingcontrol  
inputs)willimmediatelytakethedeviceoutofthepowerdownstate.  
TheIDT72V3622/72V3632/72V3642arecharacterizedforoperationfrom  
0oC to 70oC. Industrial temperature range (-40οC to +85οC) is available by  
special order. They are fabricated using high speed, submicron CMOS  
technology.  
Thesedeviceshavetwomodesofoperation:IntheIDTStandardmode,  
thefirstwordwrittentoanemptyFIFOisdepositedintothememoryarray. A  
read operation is required to access that word (along with all other words  
residinginmemory).IntheFirstWordFallThroughmode(FWFT),thefirstlong-  
word (36-bit wide) written to an empty FIFO appears automatically on the  
outputs, no read operation required (Nevertheless, accessing subsequent  
wordsdoesnecessitateaformalreadrequest).ThestateoftheFWFTpinduring  
FIFOoperationdeterminesthemodeinuse.  
Each FIFO has a combined Empty/Output Ready Flag (EFA/ORA and  
EFB/ORB)andacombinedFull/InputReadyFlag(FFA/IRAand FFB/IRB).  
TheEFandFFfunctionsareselectedintheIDTStandardmode.EFindicates  
whetherornottheFIFOmemoryisempty. FFshowswhetherthememoryis  
fullornot.TheIRandORfunctionsareselectedintheFirstWordFallThrough  
mode.IRindicateswhetherornottheFIFOhasavailablememorylocations.  
ORshowswhethertheFIFOhasdataavailableforreadingornot.Itmarksthe  
presenceofvaliddataontheoutputs.  
EachFIFOhasaprogrammableAlmost-Emptyflag(AEAandAEB)and  
aprogrammableAlmost-Fullflag(AFAandAFB). AEAandAEB indicatewhen  
3
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
PIN DESCRIPTIONS  
Symbol  
Name  
I/O  
Description  
A0-A35  
PortAData  
I/0  
O
36-bitbidirectionaldataportforsideA.  
ProgrammableAlmost-EmptyflagsynchronizedtoCLKA.ItisLOWwhenthenumberofwordsinFIFO2is  
AEA  
PortAAlmost-  
EmptyFlag  
(Port A) lessthanorequaltothevalueintheAlmost-EmptyAOffsetregister,X2.  
ProgrammableAlmost-EmptyflagsynchronizedtoCLKB.ItisLOWwhenthenumberof words in FIFO1 is  
(Port B) lessthanorequaltothevalueintheAlmost-EmptyBOffsetregister,X1.  
ProgrammableAlmost-FullflagsynchronizedtoCLKA.ItisLOWwhenthenumberofempty locationsin  
(Port A) FIFO1islessthanorequaltothevalueintheAlmost-FullAOffsetregister, Y1.  
ProgrammableAlmost-FullflagsynchronizedtoCLKB.ItisLOWwhenthenumberofempty locationsin  
(Port B) FIFO2islessthanorequaltothevalueintheAlmost-FullBOffsetregister, Y2.  
AEB  
AFA  
AFB  
PortBAlmost-  
EmptyFlag  
O
PortAAlmost-  
Full Flag  
O
PortBAlmost-  
Full Flag  
O
B0 - B35  
CLKA  
PortBData  
PortAClock  
I/O  
I
36-bitbidirectionaldataportforsideB.  
CLKA is a continuous clock that synchronizes all data transfers through port A and can be asynchronous or  
coincident to CLKB. FFA/IRA, EFA/ORA, AFA, and AEA are all synchronized to the LOW-to-HIGH  
transitionofCLKA.  
CLKB  
PortBClock  
I
CLKBisacontinuousclockthatsynchronizesalldatatransfersthroughportBand can be asynchronous or  
coincident to CLKA. FFB/IRB, EFB/ORB, AFB, and AEB are synchronized to the LOW-to-HIGH  
transitionofCLKB.  
CSA  
CSB  
Port A Chip  
Select  
I
I
CSA must be LOW to enable a LOW-to-HIGH transition of CLKA to read or write on port A. The A0-A35  
outputs are in the high-impedance state when CSA is HIGH.  
Port B Chip  
Select  
CSB must be LOW to enable a LOW-to-HIGH transition of CLKB to read or write data on port B. The  
B0- B35 outputs are in the high-impedance state when CSB is HIGH.  
EFA/ORA PortAEmpty/  
OutputReady  
O
This is a dual function pin. In the IDT Standard mode, the EFA function is selected. EFA indicates  
whether or not the FIFO2 memory is empty. In the FWFT mode, the ORA function is selected. ORA  
indicates the presence of valid data on A0-A35 outputs, available for reading. EFA/ORA is synchronized  
totheLOW-to-HIGHtransitionofCLKA.  
Flag  
EFB/ORB PortBEmpty/  
OutputReady  
O
This is a dual function pin. In the IDT Standard mode, the EFB function is selected. EFB indicates  
whether or not the FIFO1 memory is empty. In the FWFT mode, the ORB function is selected. ORB  
indicates the presence of valid data on B0-B35 outputs, available for reading. EFB/ORB is synchronized to  
theLOW-to-HIGHtransitionofCLKB.  
Flag  
ENA  
Port A Enable  
Port B Enable  
I
I
ENA must be HIGH to enable a LOW-to-HIGH transition of CLKA to read or write data on port A.  
ENB must be HIGH to enable a LOW-to-HIGH transition of CLKB to read or write data on port B.  
ENB  
FFA/IRA  
Port A Full/  
Input Ready  
Flag  
O
This is a dual function pin. In the IDT Standard mode, the FFA function is selected. FFA indicates whether  
or not the FIFO1 memory is full. In the FWFT mode, the IRA function is selected. IRA indicates whether or  
not there is space available for writing to the FIFO1 memory. FFA/IRA is synchronized to the LOW-to-  
HIGHtransitionofCLKA.  
FFB/IRB  
Port B Full/  
Input Ready  
Flag  
O
This is a dual function pin. In the IDT Standard mode, the FFB function is selected. FFB indicates whether  
or not the FIFO2 memory is full. In the FWFT mode, the IRB function is selected. IRB indicates whether or  
not there is space available for writing to the FIFO2 memory. FFB/IRB is synchronized to the LOW-to-  
HIGHtransitionofCLKB.  
FWFT  
FirstWordFall  
Through Mode  
I
I
Thispinselectsthetimingmode. AHIGHonFWFTselectsIDTStandardmode, aLOWselectsFirst  
Word Fall Through mode. Once the timing mode has been selected, the level on FWFT must be static  
throughoutdeviceoperation.  
FS1, FS0  
FlagOffset  
Selects  
A LOW-to-HIGH transition of the FIFO Reset input latches the values of FS0 and FS1. If either FS0 or  
FS1 is HIGH when the FIFO Reset input goes HIGH, one of three preset values is selected as the  
offset for FIFOs Almost-Full and Almost-Empty flags. If both FIFOs are reset simultaneously and both  
FS0 and FS1 are LOW when RST1 and RST2 go HIGH, the first four writes to FIFO1 load the Almost-  
Empty and Almost-Full offsets for both FIFOs.  
4
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
PINDESCRIPTIONS(CONTINUED)  
Symbol  
Name  
I/O  
Description  
MBA  
Port A Mailbox  
Select  
I
A HIGH level on MBA chooses a mailbox register for a port A read or write operation. When the  
A0-A35 outputs are active, a HIGH level on MBA selects data from the mail2 register for output and a  
LOWlevelselectsFIFO2outputregisterdataforoutput.  
MBB  
Port B Mailbox  
Select  
I
A HIGH level on MBB chooses a mailbox register for a port B read or write operation. When the  
B0-B35 outputs are active, a HIGH level on MBB selects data from the mail1 register or output and a  
LOWlevelselectsFIFO1outputregisterdataforoutput.  
MBF1  
Mail1Register  
Flag  
O
MBF1 is set LOW by a LOW-to-HIGH transition of CLKA that writes data to the mail1 register.  
Writes to the mail1 register are inhibited while MBF1 is LOW. MBF1 is set HIGH by a LOW-to-HIGH  
transition of CLKB when a port B read is selected and MBB is HIGH. MBF1 is set HIGH when FIFO1  
isreset.  
MBF2  
Mail2Register  
Flag  
O
MBF2issetLOWbyaLOW-to-HIGHtransitionofCLKBthatwritesdata tothemail2register.Writes  
to the mail2 register are inhibited while MBF2 is LOW. MBF2 is set HIGH by a LOW-to-HIGH  
transition of CLKA when a port A read is selected and MBA is HIGH. MBF2 is also set HIGH when  
FIFO2 is reset.  
RST1  
RST2  
FIFO1Reset  
FIFO2Reset  
I
I
ToresetFIFO1,fourLOW-to-HIGHtransitionsofCLKAandfourLOW-to-HIGHtransitionsofCLKBmust  
occur while RST1 is LOW. The LOW-to-HIGH transition of RST1 latches the status of FS0 and FS1 for  
AFA and AEB offset selection. FIFO1 must be reset upon power up before data is written to its RAM.  
ToresetFIFO2,fourLOW-to-HIGHtransitionsofCLKAandfourLOW-to-HIGHtransitionsofCLKBmust  
occur while RST2 is LOW. The LOW-to-HIGH transition of RST2 latches the status of FS0 and FS1 for  
AFB and AEA offset selection. FIFO2 must be reset upon power up before data is written to its RAM.  
W/RA  
PortAWrite/  
ReadSelect  
I
I
A HIGH selects a write operation and a LOW selects a read operation on port A for a LOW-to-HIGH  
transition of CLKA. The A0-A35 outputs are in the HIGH impedance state when W/RA is HIGH.  
W/RB  
PortBWrite/  
ReadSelect  
A LOW selects a write operation and a HIGH selects a read operation on port B for a LOW-to-HIGH  
transition of CLKB. The B0-B35 outputs are in the HIGH impedance state when W/RB is LOW.  
5
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
ABSOLUTEMAXIMUMRATINGSOVEROPERATING  
TEMPERATURERANGE(Unlessotherwisenoted)(1)  
Symbol  
Rating  
Commercial  
–0.5to+4.6  
–0.5toVCC+0.5  
–0.5toVCC+0.5  
±20  
Unit  
V
VCC  
VI(2)  
VO(2)  
IIK  
SupplyVoltageRange  
InputVoltageRange  
V
OutputVoltageRange  
V
Input Clamp Current (VI < 0 or VI > VCC)  
Output Clamp Current (VO = < 0 or VO > VCC)  
Continuous Output Current (VO = 0 to VCC)  
ContinuousCurrentThroughVCC or GND  
StorageTemperatureRange  
mA  
mA  
mA  
mA  
ο C  
IOK  
±50  
IOUT  
ICC  
±50  
±400  
TSTG  
–65to150  
NOTES:  
1. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these  
or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute maximum rated conditions for extended periods may affect  
device reliability.  
2. The input and output voltage ratings may be exceeded provided the input and output current ratings are observed.  
RECOMMENDEDOPERATINGCONDITIONS  
Symbol  
VCC(1)  
VIH  
Parameter  
Min.  
3.0  
2
Typ.  
3.3  
Max.  
3.6  
Unit  
V
SupplyVoltage  
High-LevelInputVoltage  
Low-LevelInputVoltage  
High-LevelOutputCurrent  
Low-LevelOutputCurrent  
OperatingTemperature  
VCC+0.5  
0.8  
V
VIL  
0
V
IOH  
–4  
mA  
mA  
°C  
IOL  
8
TA  
70  
NOTE:  
1. For 10ns (100 MHz operation), Vcc=3.3V +/- 0.15V, TA = 0° to +70°C; JEDEC JESD8-A compliant.  
ELECTRICALCHARACTERISTICSOVERRECOMMENDED  
OPERATINGTEMPERATURERANGE(Unlessotherwisenoted)  
IDT72V3622  
IDT72V3632  
IDT72V3642  
Commercial  
tCLK = 10(1), 15ns  
Symbol  
VOH  
Parameter  
Test Conditions  
IOH = –4 mA  
Min.  
Typ.(2)  
Max.  
Unit  
V
OutputLogic"1"Voltage  
VCC = 3.0V,  
VCC = 3.0V,  
VCC = 3.6V,  
VCC = 3.6V,  
VCC = 3.6V,  
VCC = 3.6V,  
VI = 0,  
2.4  
0.5  
±10  
±10  
5
VOL  
OutputLogic"0"Voltage  
IOL = 8 mA  
V
ILI  
InputLeakageCurrent(AnyInput)  
OutputLeakageCurrent  
VI = VCC or 0  
VO = VCC or 0  
μA  
μA  
mA  
mA  
pF  
ILO  
ICC2(3)  
ICC3(3)  
CIN(4)  
COUT(4)  
Standby Current (with CLKA and CLKB running)  
StandbyCurrent(noclocksrunning)  
InputCapacitance  
VI = VCC - 0.2V or 0  
VI = VCC - 0.2V or 0  
f = 1 MHz  
1
4
OutputCapacitance  
VO = 0,  
f = 1 MHZ  
8
pF  
NOTES:  
1. For 10ns speed grade only: VCC = 3.3V +/- 0.15V, TA = 0° to +70°C; JEDEC JESD8-A compliant.  
2. All typical values are at VCC = 3.3V, TA = 25°C.  
3. For additional ICC information, see Figure 1, Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS).  
4. Characterized values, not currently tested.  
5. Industrial temperature range is available by special order.  
6
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
DETERMINING ACTIVE CURRENT CONSUMPTION AND POWER DISSIPATION  
The ICC(f) current for the graph in Figure 1 was taken while simultaneously reading and writing a FIFO on the IDT72V3622/72V3632/72V3642 with  
CLKAandCLKBsettofS. Alldatainputsanddataoutputschangestateduringeachclockcycletoconsumethehighestsupplycurrent. Dataoutputswere  
disconnectedtonormalizethegraphtoazerocapacitanceload. Oncethecapacitanceloadperdata-outputchannelandthenumberofthesedevice's  
inputs driven by TTL HIGH levels are known, the power dissipation can be calculated with the equation below.  
CALCULATING POWER DISSIPATION  
With ICC(f) taken from Figure 1, the maximum power dissipation (PT) of these FIFOs may be calculated by:  
2
PT = VCC x ICC(f) + Σ(CL x VCC X fo)  
N
where:  
N
=
=
=
number of outputs = 36  
CL  
fo  
output capacitance load  
switchingfrequencyofanoutput  
200  
175  
150  
f
data = 1/2 fS  
T
A
= 25οC  
L = 0 pF  
VCC = 3.6V  
C
VCC = 3.3V  
125  
100  
VCC = 3.0V  
75  
50  
25  
0
80  
100  
0
10  
20  
30  
40  
50  
60  
70  
90  
4660 drw 03a  
fS  
Clock Frequency MHz  
Figure 1. Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS)  
7
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
TIMING REQUIREMENTS OVER RECOMMENDED RANGES OF SUPPLY  
VOLTAGEANDOPERATINGTEMPERATURE  
Commercial: VCC=3.3V± 0.30V; for 10ns (100 MHz) operation, VCC=3.3V ±0.15V; TA = 0ο C to +70ο C; JEDEC JESD8-A compliant  
IDT72V3622L10(1)  
IDT72V3632L10(1)  
IDT72V3642L10(1)  
IDT72V3622L15  
IDT72V3632L15  
IDT72V3642L15  
Symbol  
fS  
Parameter  
Min.  
10  
4.5  
4.5  
3
Max.  
100  
Min.  
15  
6
Max.  
66.7  
Unit  
MHz  
ns  
Clock Frequency, CLKA or CLKB  
tCLK  
Clock Cycle Time, CLKA or CLKB  
tCLKH  
tCLKL  
tDS  
Pulse Duration, CLKA or CLKB HIGH  
ns  
Pulse Duration, CLKA and CLKB LOW  
Setup Time, A0-A35 before CLKAand B0-B35 before CLKB↑  
SetupTimeCSAbeforeCLKA;CSBbeforeCLKB↑  
6
ns  
4
ns  
tENS1  
tENS2  
4
4.5  
4.5  
ns  
Setup Time ENA, W/RA and MBA before CLKA; ENB, W/RB and MBB  
beforeCLKB↑  
3
ns  
(2)  
tRSTS  
tFSS  
tFWS  
tDH  
Setup Time, RST1 or RST2 LOW before CLKAor CLKB↑  
5
5
7.5  
0
ns  
ns  
ns  
ns  
ns  
Setup Time, FS0 and FS1 before RST1 and RST2 HIGH  
SetupTime, FWFTbeforeCLKA↑  
7.5  
0
Hold Time, A0-A35 after CLKA  
and B0-B35 after CLKB  
0.5  
0.5  
1
tENH  
Hold Time, CSA, W/RA, ENA, and MBA after CLKA; CSB, W/RB, ENB, and  
1
MBBafterCLKB↑  
(2)  
tRSTH  
tFSH  
tSKEW1(3)  
Hold Time, RST1 or RST2 LOW after CLKA  
or CLKB  
4
2
4
2
ns  
ns  
ns  
Hold Time, FS0 and FS1 after RST1 and RST2 HIGH  
Skew Time, between CLKA  
and CLKB  
for EFA/ORA, EFB/ORB, FFA/IRA,  
7.5  
7.5  
and FFB/IRB  
tSKEW2(3,4) Skew Time, between CLKAand CLKBfor AEA, AEB, AFA, and AFB  
12  
12  
ns  
NOTES:  
1. For 10ns speed grade only: VCC = 3.3V +/- 0.15V, TA = 0° to +70°C; JEDEC JESD8-A compliant.  
2. Requirement to count the clock edge as one of at least four needed to reset a FIFO.  
3. Skew time is not a timing constraint for proper device operation and is only included to illustrate the timing relationship between CLKA cycle and CLKB cycle.  
4. Design simulated, not tested.  
5. Industrial temperature range is available by special order.  
8
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
SWITCHING CHARACTERISTICS OVER RECOMMENDED RANGES OF SUPPLY  
VOLTAGE AND OPERATING TEMPERATURE, CL = 30 pF  
Commercial: VCC=3.3V± 0.30V; for 10ns (100 MHz) operation, VCC=3.3V ±0.15V; TA = 0ο C to +70ο C; JEDEC JESD8-A compliant  
IDT72V3622L10(1) IDT72V3622L15  
IDT72V3632L10(1) IDT72V3632L15  
IDT72V3642L10(1) IDT72V3642L15  
Symbol  
tA  
Parameter  
Min.  
Max.  
6.5  
6.5  
6.5  
6.5  
6.5  
6.5  
Min.  
Max.  
Unit  
ns  
AccessTime, CLKAtoA0-A35andCLKBtoB0-B35  
Propagation Delay Time, CLKAto FFA/IRA and CLKBto FFB/IRB  
Propagation Delay Time, CLKAto EFA/ORA and CLKBto EFB/ORB  
Propagation Delay Time, CLKAto AEA and CLKBto AEB  
Propagation Delay Time, CLKAto AFA and CLKBto AFB  
2
2
1
1
1
0
2
2
1
1
1
0
10  
8
tWEF  
tREF  
tPAE  
tPAF  
tPMF  
ns  
8
ns  
8
ns  
8
ns  
Propagation Delay Time, CLKAto MBF1 LOW or MBF2 HIGH and CLKBto  
MBF2 LOW or MBF1 HIGH  
8
ns  
tPMR  
tMDV  
tRSF  
Propagation Delay Time, CLKAto B0-B35(2) and CLKBto A0-A35(3)  
2
2
1
8
2
2
1
10  
10  
15  
ns  
ns  
ns  
Propagation Delay Time, MBA to A0-A35 valid and MBB to B0-B35 Valid  
6.5  
10  
Propagation Delay Time, RST1 LOW to AEB LOW, AFA HIGH, and MBF1 HIGH,  
and RST2 LOW to AEA LOW, AFB HIGH, and MBF2 HIGH  
tEN  
tDIS  
Enable Time, CSA and W/RA LOW to A0-A35 Active and CSB LOW and W/RB  
2
1
6
6
2
1
10  
8
ns  
ns  
HIGH to B0-B35 Active  
Disable Time, CSA or W/RA HIGH to A0-A35 at high-impedance and CSB HIGH or  
W/RB LOW to B0-B35 at high-impedance  
NOTES:  
1. For 10ns speed grade only: VCC = 3.3V +/- 0.15V, TA = 0° to +70°C; JEDEC JESD8-A compliant.  
2. Writing data to the mail1 register when the B0-B35 outputs are active and MBB is HIGH.  
3. Writing data to the mail2 register when the A0-A35 outputs are active and MBA is HIGH.  
4. Industrial temperature range is available by special order.  
9
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
FollowingReset,thelevelappliedtotheFWFTinputtochoosethedesired  
timingmodemustremainstaticthroughoutFIFOoperation.RefertoFigure2  
(Reset)foraFirstWordFallThroughselecttimingdiagram.  
SIGNAL DESCRIPTION  
RESET  
Afterpowerup,aMasterResetoperationmustbeperformedbyproviding  
a LOW pulse to RST1 and RST2 simultaneously. Afterwards, the FIFO  
memories of the IDT72V3622/72V3632/72V3642 are reset separately by  
taking their Reset (RST1, RST2) inputs LOW for at least four port-A Clock  
(CLKA)andfourport-BClock(CLKB)LOW-to-HIGHtransitions. TheReset  
inputs can switch asynchronously to the clocks. A FIFO reset initializes the  
internalreadandwritepointersandforcestheInputReadyflag(IRA,IRB)LOW,  
theOutputReadyflag(ORA,ORB)LOW,theAlmost-Emptyflag(AEA,AEB)  
LOW,andtheAlmost-Fullflag(AFA,AFB)HIGH. ResettingaFIFOalsoforces  
theMailboxFlag(MBF1, MBF2)oftheparallelmailboxregisterHIGH. After  
aFIFOisreset,itsInputReadyflagissetHIGHaftertwoclockcyclestobegin  
normaloperation.  
ALOW-to-HIGHtransitiononaFIFOReset(RST1,RST2)inputlatches  
thevalueoftheFlagSelect(FS0,FS1)inputsforchoosingtheAlmost-Fulland  
Almost-Empty offset programming method. (For details see Table 1, Flag  
Programming,andtheProgrammingtheAlmost-EmptyandAlmost-FullFlags  
section). The relevant FIFO Reset timing diagram can be found in Figure 2.  
ALMOST-EMPTYFLAGANDALMOST-FULLFLAGOFFSETPROGRAM-  
MING  
Fourregistersinthesedevicesareusedtoholdtheoffsetvaluesforthe  
Almost-EmptyandAlmost-Fullflags.TheportBAlmost-Emptyflag(AEB)Offset  
registerislabeledX1andtheportAAlmost-Emptyflag(AEA)Offsetregister  
is labeled X2. The port A Almost-Full flag (AFA) Offset register is labeled Y1  
andtheportBAlmost-Fullflag(AFB)OffsetregisterislabeledY2.Theindex  
ofeachregisternamecorrespondstoitsFIFOnumber.Theoffsetregisterscan  
be loaded with preset values during the reset of a FIFO or they can be  
programmed from port A (see Table 1).  
FS0 and FS1 function the same way in both IDT Standard and FWFT  
modes.  
— PRESET VALUES  
ToloadtheFIFO'sAlmost-EmptyflagandAlmost-FullflagOffsetregisters  
withoneofthethreepresetvalueslistedinTable1,atleastoneoftheflagselect  
inputsmustbeHIGHduringtheLOW-to-HIGHtransitionofitsresetinput.For  
example,toloadthepresetvalueof64intoX1andY1,FS0andFS1mustbe  
HIGH when FlFO1 Reset (RST1) returns HIGH. Flag offset registers  
associatedwithFIFO2areloadedwithoneofthepresetvaluesinthesameway  
withFIFO2Reset(RST2)toggledsimultaneouslywithFIFO1Reset(RST1).  
For preset value loading timing diagram, see Figure 2.  
FIRST WORD FALL THROUGH (FWFT)  
AfterMasterReset,theFWFTselectfunctionisactive,permittingachoice  
between two possible timing modes: IDT Standard mode or First Word Fall  
Through (FWFT) mode. Once the Reset (RST1, RST2) input is HIGH, a  
HIGH on the FWFT input during the next LOW-to-HIGH transition of CLKA  
(forFIFO1)andCLKB(forFIFO2)willselectIDTStandardmode.Thismode  
uses the Empty Flag function (EFA, EFB) to indicate whether or not there  
areanywordspresentintheFIFOmemory.ItusestheFullFlagfunction(FFA,  
FFB) to indicate whether or not the FIFO memory has any free space for  
writing.InIDTStandardmode,everywordreadfromtheFIFO,includingthe  
first,mustberequestedusingaformalreadoperation.  
OncetheReset(RST1, RST2)inputisHIGH, aLOWontheFWFTinput  
duringthenextLOW-to-HIGHtransitionofCLKA(forFIFO1)andCLKB(for  
FIFO2) will select FWFT mode. This mode uses the Output Ready function  
(ORA,ORB)toindicatewhetherornotthereisvaliddataatthedataoutputs  
(A0-A35orB0-B35).ItalsousestheInputReadyfunction(IRA,IRB)toindicate  
whetherornottheFIFOmemoryhasanyfreespaceforwriting.IntheFWFT  
mode,thefirstwordwrittentoanemptyFIFOgoesdirectlytodataoutputs,no  
readrequestnecessary. Subsequentwordsmustbeaccessedbyperforming  
aformalreadoperation.  
— PARALLEL LOAD FROM PORT A  
ToprogramtheX1,X2,Y1,andY2registersfromportA,bothFlFOsshould  
be reset simultaneously with FS0 and FS1 LOW during the LOW-to-HIGH  
transitionoftheResetinputs.Afterthisresetiscomplete,thefirstfourwritesto  
FIFO1donotstoredataintheFIFOmemorybutloadtheoffsetregistersinthe  
order Y1, X1, Y2, X2. The port A data inputs used by the offset registers are  
(A7-A0), (A8-A0), or (A9-A0) for the IDT72V3622, IDT72V3632, or  
IDT72V3642,respectively. Thehighestnumberedinputisusedasthemost  
significantbitofthebinarynumberineachcase. Validprogrammingvaluesfor  
the registers ranges from 1 to 252 for the IDT72V3622; 1 to 508 for the  
IDT72V3632;and1to1,020fortheIDT72V3642. Afteralltheoffsetregisters  
areprogrammedfromportA,theportBFull/InputReadyflag(FFB/IRB)isset  
HIGH,andbothFIFOsbeginnormaloperation.SeeFigure3forrelevantoffset  
registerparallelprogrammingtimingdiagram.  
TABLE 1 — FLAG PROGRAMMING  
FS1  
FS0  
RST1  
RST2  
X1 AND Y1 REGlSTERS(1)  
X2 AND Y2 REGlSTERS(2)  
H
H
H
H
L
H
H
L
X
X
X
X
X
X
64  
X
X
64  
16  
X
L
X
16  
H
H
L
8
X
L
X
8
L
Parallel programming via Port A  
Parallel programming via Port A  
NOTES:  
1. X1 register holds the offset for AEB; Y1 register holds the offset for AFA.  
2. X2 register holds the offset for AEA; Y2 register holds the offset for AFB.  
10  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
FIFO WRITE/READ OPERATION  
andarenotrelatedtohigh-impedancecontrolofthedataoutputs.Ifaportenable  
ThestateoftheportAdata(A0-A35)outputsiscontrolledbyportAChip isLOWduringaclockcycle,theport’sChipSelectandWrite/Readselectmay  
Select(CSA)andportAWrite/Readselect(W/RA).TheA0-A35outputsare changestatesduringthesetupandholdtimewindowofthecycle.  
inthehigh-impedancestatewheneitherCSAorW/RAisHIGH.TheA0-A35  
outputs are active when both CSA and W/RA are LOW.  
WhenoperatingtheFIFOinFWFTmodeandtheOutputReadyflagisLOW,  
thenextwordwrittenisautomaticallysenttotheFIFO’soutputregisterbythe  
Data is loaded into FIFO1 from the A0-A35 inputs on a LOW-to-HIGH LOW-to-HIGHtransitionoftheportclockthatsetstheOutputReadyflagHIGH.  
transitionofCLKAwhenCSAisLOW, W/RAisHIGH, ENAisHIGH, MBAis WhentheOutputReadyflagisHIGH,subsequentdataisclockedtotheoutput  
LOW,andFFA/IRAisHIGH. DataisreadfromFIFO2totheA0-A35outputs registersonlywhenareadisselectedusingtheport’sChipSelect,Write/Read  
byaLOW-to-HIGHtransitionofCLKAwhenCSAisLOW,W/RAisLOW,ENA select,Enable,andMailboxselect.  
isHIGH,MBAisLOW,andEFA/ORAisHIGH(seeTable2).FIFOreadsand  
writesonportAareindependentofanyconcurrentportBoperation.Writeand theEmptyFlagtochangestateonthesecondLOW-to-HIGHtransitionofthe  
Read cycle timing diagrams for Port A can be found in Figure 4 and 7. ReadClock. Thedatawordwillnotbeautomaticallysenttotheoutputregister.  
WhenoperatingtheFIFOinIDTStandardmode,thefirstwordwillcause  
TheportBcontrolsignalsareidenticaltothoseofportAwiththeexception Instead, data residing in the FIFO's memory array is clocked to the output  
thattheportBWrite/Readselect(W/RB)istheinverseoftheportAWrite/Read registeronlywhenareadisselected usingtheport’sChipSelect,Write/Read  
select(W/RA).ThestateoftheportBdata(B0-B35)outputsiscontrolledbythe select,Enable,andMailboxselect.  
portBChipSelect(CSB)andportBWrite/Readselect(W/RB). TheB0-B35  
outputs are in the high-impedance state when either CSB is HIGH or W/RB SYNCHRONIZED FIFO FLAGS  
isLOW.TheB0-B35outputsareactivewhenCSBisLOWandW/RBisHIGH.  
EachFIFOissynchronizedtoitsportclockthroughatleasttwoflip-flop  
Data is loaded into FIFO2 from the B0-B35 inputs on a LOW-to-HIGH stages.Thisisdonetoimproveflagsignalreliabilitybyreducingtheprobability  
transition of CLKB when CSB is LOW, W/RB is LOW, ENB is HIGH, MBB is ofmetastableeventswhenCLKAandCLKBoperateasynchronouslytoone  
LOW, andFFB/IRBisHIGH. DataisreadfromFIFO1totheB0-B35outputs another. EFA/ORA, AEA, FFA/IRA, and AFA are synchronized to CLKA.  
byaLOW-to-HIGHtransitionofCLKBwhenCSBisLOW,W/RBisHIGH,ENB EFB/ORB, AEB, FFB/IRB, and AFB are synchronized to CLKB. Tables  
isHIGH,MBBisLOW,andEFB/ORBisHIGH(seeTable3).FIFOreadsand 4 and 5 show the relationship of each port flag to FIFO1 and FIFO2.  
writesonportBareindependentofanyconcurrentportAoperation.Writeand  
Read cycle timing diagrams for Port B can be found in Figure 5 and 6.  
The setup and hold time constraints to the port Clocks for the port Chip  
EMPTY/OUTPUT READY FLAGS (EFA/ORA, EFB/ORB)  
These are dual purpose flags. In the FWFT mode, the Output Ready  
SelectsandWrite/Readselectsareonlyforenablingwriteandreadoperations (ORA, ORB) function is selected. When the Output Ready flag is HIGH,  
TABLE 2 — PORT A ENABLE FUNCTION TABLE  
CSA  
H
L
W/RA  
ENA  
MBA  
CLKA  
Data A (A0-A35) I/O  
High-Impedance  
Input  
Port Function  
X
H
H
H
L
X
X
X
X
X
X
None  
None  
L
X
L
H
L
Input  
FIFO1 write  
Mail1write  
L
H
H
Input  
L
L
L
Output  
None  
L
L
H
L
Output  
FIFO2 read  
None  
L
L
L
H
Output  
L
L
H
H
Output  
Mail2 read (set MBF2 HIGH)  
TABLE 3 — PORT B ENABLE FUNCTION TABLE  
CSB  
H
L
W/RB  
ENB  
MBB  
CLKB  
Data B (B0-B35) I/O  
Port Function  
X
L
X
X
X
X
X
X
High-Impedance  
Input  
None  
None  
L
X
L
L
H
L
Input  
FIFO2 write  
Mail2write  
L
L
H
H
Input  
L
H
H
H
H
L
L
Output  
None  
L
H
L
Output  
FIFO1 read  
None  
L
L
H
Output  
L
H
H
Output  
Mail1 read (set MBF1 HIGH)  
11  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
newdataispresentintheFIFOoutputregister.WhentheOutputReadyflag  
InIDTStandardmode,fromthetimeawordiswrittentoaFIFO,theEmpty  
is LOW, the previous data word is present in the FIFO output register and Flagwillindicatethepresenceofdataavailableforreadinginaminimumoftwo  
attemptedFIFOreadsareignored. cyclesoftheEmptyFlagsynchronizingclock.Therefore,anEmptyFlagisLOW  
In the IDT Standard mode, the Empty Flag (EFA, EFB) function is ifawordinmemoryisthenextdatatobesenttotheFlFOoutputregisterand  
selected.WhentheEmptyFlagisHIGH,dataisavailableintheFIFO’sRAM twocyclesoftheportClockthatreadsdatafromtheFIFOhavenotelapsed  
forreadingtotheoutputregister.WhentheEmptyFlagisLOW,theprevious sincethetimethewordwaswritten.TheEmptyFlagoftheFIFOremainsLOW  
datawordispresentintheFIFOoutputregisterandattemptedFIFOreadsare untilthesecondLOW-to-HIGHtransitionofthesynchronizingclockoccurs,  
ignored.  
TheEmpty/OutputReadyflagofaFIFOissynchronizedtotheportclock  
forcing the Empty Flag HIGH; only then can data be read.  
ALOW-to-HIGHtransitiononanEmpty/OutputReadyflagsynchronizing  
thatreadsdatafromitsarray. ForboththeFWFTandIDTStandardmodes, clockbeginsthefirstsynchronizationcycleofawriteiftheclocktransitionoccurs  
the FIFO read pointer is incremented each time a new word is clocked to its attimetSKEW1orgreaterafterthewrite.Otherwise,thesubsequentclockcycle  
outputregister.ThestatemachinethatcontrolsanOutputReadyflagmonitors canbethefirstsynchronizationcycle(seeFigures8through11forEFA/ORA  
a write pointer and read pointer comparator that indicates when the FIFO and EFB/ORB timing diagrams).  
memorystatusisempty,empty+1,orempty+2.  
InFWFTmode,fromthetimeawordiswrittentoaFIFO,itcanbeshifted FULL/INPUT READY FLAGS (FFA/IRA, FFB/IRB)  
totheFIFOoutputregisterinaminimumofthreecyclesoftheOutputReady  
Thisisadualpurposeflag.InFWFTmode,theInputReady(IRAandIRB)  
flagsynchronizingclock.Therefore,anOutputReadyflagisLOWifawordin function is selected. In IDT Standard mode, the Full Flag (FFA and FFB)  
memoryisthenextdatatobesenttotheFlFOoutputregisterandthreecycles functionisselected.Forbothtimingmodes,whentheFull/InputReadyflagis  
oftheportClockthatreadsdatafromtheFIFOhavenotelapsedsincethetime HIGH,amemorylocationisfreeintheFIFOtoreceivenewdata.Nomemory  
thewordwaswritten.TheOutputReadyflagoftheFIFOremainsLOWuntil locationsarefreewhentheFull/InputReadyflagisLOWandattemptedwrites  
thethirdLOW-to-HIGHtransitionofthesynchronizingclockoccurs,simulta- to the FIFO are ignored.  
neouslyforcingtheOutputReadyflagHIGHandshiftingthewordtotheFIFO  
outputregister.  
TABLE 4 — FIFO1 FLAG OPERATION (IDT STANDARD AND FWFT MODES)  
Synchronized  
to CLKB  
Synchronized  
to CLKA  
Number of Words in FIFO(1,2)  
IDT72V3622(3)  
IDT72V3632(3)  
IDT72V3642(3)  
EFB/ORB  
AEB  
L
AFA  
FFA/IRA  
0
1 to X1  
0
1 to X1  
0
1 to X1  
L
H
H
H
H
H
H
H
L
H
H
H
H
L
L
(X1+1) to [256-(Y1+1)]  
(256-Y1) to 255  
256  
(X1+1) to [512-(Y1+1)]  
(512-Y1) to 511  
512  
(X1+1) to [1,024-(Y1+1)]  
(1,024-Y1) to 1,023  
1,024  
H
H
H
L
NOTES:  
1. When a word loaded to an empty FIFO is shifted to the output register, its previous FIFO memory location is free.  
2. Data in the output register does not count as a "word in FIFO memory". Since in FWFT mode, the first word written to an empty FIFO goes unrequested to the output register (no  
read operation necessary), it is not included in the FIFO memory count.  
3. X1 is the Almost-Empty offset for FIFO1 used by AEB. Y1 is the Almost-Full offset for FIFO1 used by AFA. Both X1 and Y1 are selected during a reset of FIFO1 or programmed from  
port A.  
4. The ORB and IRA functions are active during FWFT mode; the EFB and FFA functions are active in IDT Standard mode.  
TABLE 5 — FIFO2 FLAG OPERATION (IDT STANDARD AND FWFT MODES)  
Synchronized  
to CLKA  
Synchronized  
to CLKB  
Number of Words in FIFO(1,2)  
IDT72V3622(3)  
IDT72V3632(3)  
IDT72V3642(3)  
EFA/ORA  
AEA  
L
AFB  
FFB/IRB  
0
1 to X2  
0
1 to X2  
0
1 to X2  
L
H
H
H
H
H
H
H
L
H
H
H
H
L
L
(X2+1) to [256-(Y2+1)]  
(256-Y2) to 255  
256  
(X2+1) to [512-(Y2+1)]  
(512-Y2) to 511  
512  
(X2+1) to [1,024-(Y2+1)]  
(1,024-Y2) to 1,023  
1,024  
H
H
H
L
NOTES:  
1. When a word loaded to an empty FIFO is shifted to the output register, its previous FIFO memory location is free.  
2. Data in the output register does not count as a "word in FIFO memory". Since in FWFT mode, the first word written to an empty FIFO goes unrequested to the output register (no  
read operation necessary), it is not included in the FIFO memory count.  
3. X2 is the Almost-Empty offset for FIFO2 used by AEA. Y2 is the Almost-Full offset for FIFO2 used by AFB. Both X2 and Y2 are selected during a reset of FIFO2 or programmed from  
port A.  
4. The ORA and IRB functions are active during FWFT mode; the EFA and FFB functions are active in IDT Standard mode.  
12  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
TheFull/InputReadyflagofaFlFOissynchronizedtotheportclockthat bythecontentsofregisterY1forAFAandregisterY2forAFB.Theseregisters  
writesdatatoitsarray. ForbothFWFTandIDTStandardmodes, eachtime are loaded with preset values during a FlFO reset or programmed from port  
awordiswrittentoaFIFO,itswritepointerisincremented.Thestatemachine A(seeAlmost-EmptyflagandAlmost-Fullflagoffsetprogrammingsection).  
thatcontrolsaFull/InputReadyflagmonitorsawritepointerandreadpointer AnAlmost-FullflagisLOWwhenthenumberofwordsinitsFIFOisgreaterthan  
comparatorthatindicateswhentheFlFOmemorystatusisfull,full-1,orfull-2. orequalto(256-Y),(512-Y),or(1,024-Y)fortheIDT72V3622,IDT72V3632,  
FromthetimeawordisreadfromaFIFO,itspreviousmemorylocationisready or IDT72V3642 respectively. An Almost-Full flag is HIGH when the number  
to be written to in a minimum of two cycles of the Full/Input Ready flag of words in its FIFO is less than or equal to [256-(Y+1)], [512-(Y+1)], or  
synchronizingclock.Therefore,aFull/InputReadyflagisLOWiflessthantwo [1,024-(Y+1)] for the IDT72V3622, IDT72V3632, or IDT72V3642 respec-  
cyclesoftheFull/InputReadyflagsynchronizingclockhaveelapsedsincethe tively. NotethatadatawordpresentintheFIFOoutputregisterhasbeenread  
next memory write location has been read. The second LOW-to-HIGH frommemory.  
transitionontheFull/InputReadyflagsynchronizingclockafterthereadsets  
the Full/Input Ready flag HIGH.  
TwoLOW-to-HIGHtransitionsoftheAlmost-Fullflagsynchronizingclock  
arerequiredafteraFIFOreadforitsAlmost-Fullflagtoreflectthenewlevelof  
ALOW-to-HIGHtransitiononaFull/InputReadyflagsynchronizingclock fill.Therefore,theAlmost-FullflagofaFIFOcontaining[256/512/1,024-(Y+1)]  
beginsthefirstsynchronizationcycleofareadiftheclocktransitionoccursat or less words remains LOW if two cycles of its synchronizing clock have not  
timetSKEW1orgreateraftertheread.Otherwise,thesubsequentclockcyclecan elapsedsincethereadthatreducedthenumberofwordsinmemoryto[256/  
bethefirstsynchronizationcycle(seeFigures12through15forFFA/IRAand 512/1,024-(Y+1)]. AnAlmost-FullflagissetHIGHbythesecondLOW-to-HIGH  
FFB/IRB timing diagrams).  
transitionofitssynchronizingclockaftertheFIFOreadthatreducesthenumber  
ofwordsinmemoryto[256/512/1,024-(Y+1)]. ALOW-to-HIGHtransitionofan  
Almost-Fullflagsynchronizingclockbeginsthefirstsynchronizationcycleifit  
ALMOST-EMPTY FLAGS (AEA, AEB)  
TheAlmost-EmptyflagofaFIFOissynchronizedtotheportclockthatreads occursattimetSKEW2orgreaterafterthereadthatreducesthenumberofwords  
datafromitsarray.ThestatemachinethatcontrolsanAlmost-Emptyflagmonitors inmemoryto[256/512/1,024-(Y+1)]. Otherwise,thesubsequentsynchroniz-  
a write pointer and read pointer comparator that indicates when the FIFO ingclockcyclemaybethefirstsynchronizationcycle (seeFigures18and19).  
memory status is almost-empty, almost-empty+1, or almost-empty+2. The  
almost-emptystateisdefinedbythecontentsofregisterX1forAEBandregister  
X2forAEA.TheseregistersareloadedwithpresetvaluesduringaFIFOreset  
orprogrammedfromportA(seeAlmost-EmptyflagandAlmost-Fullflagoffset  
programmingsection).AnAlmost-EmptyflagisLOWwhenitsFIFOcontains  
X or less words and is HIGH when its FIFO contains (X+1) or more words. A  
data word present in the FIFO output register has been read from memory.  
TwoLOW-to-HIGHtransitionsoftheAlmost-Emptyflagsynchronizing  
clockarerequiredafteraFIFOwriteforitsAlmost-Emptyflagtoreflectthenew  
leveloffill.Therefore,theAlmost-FullflagofaFIFOcontaining(X+1)ormore  
wordsremainsLOWiftwocyclesofitssynchronizingclockhavenotelapsed  
sincethewritethatfilledthememorytothe(X+1)level. AnAlmost-Emptyflag  
issetHIGHbythesecondLOW-to-HIGHtransitionofitssynchronizingclockafter  
theFIFOwritethatfillsmemorytothe(X+1)level.ALOW-to-HIGHtransitionof  
anAlmost-Emptyflagsynchronizingclockbeginsthefirstsynchronizationcycle  
ifitoccursattimetSKEW2orgreaterafterthewritethatfillstheFIFOto(X+1)words.  
Otherwise,thesubsequentsynchronizingclockcyclemaybethefirstsynchro-  
nization cycle. (See Figures 16 and 17).  
MAILBOX REGISTERS  
Each FIFO has a 36-bit bypass register to pass command and control  
informationbetweenportAandportBwithoutputtingitinqueue.TheMailbox  
select(MBA,MBB)inputschoosebetweenamailregisterandaFIFOforaport  
datatransferoperation.ALOW-to-HIGHtransitiononCLKAwritesA0-A35data  
tothemail1registerwhenaportAWriteisselectedbyCSA,W/RA,andENA  
andwithMBAHIGH.ALOW-to-HIGHtransitiononCLKBwritesB0-B35data  
tothemail2registerwhenaportBWriteisselectedbyCSB,W/RB,andENB  
andwithMBBHIGH.Writingdatatoamailregistersetsitscorrespondingflag  
(MBF1orMBF2)LOW. Attemptedwritestoamailregisterareignoredwhile  
themailflagisLOW.  
Whendataoutputsofaportareactive,thedataonthebuscomesfromthe  
FIFOoutputregisterwhentheportMailboxselectinputisLOWandfromthemail  
registerwhentheportmailboxselectinputisHIGH. TheMail1RegisterFlag  
(MBF1)issetHIGHbyaLOW-to-HIGHtransitiononCLKBwhenaportBRead  
isselectedbyCSB,W/RB,andENBandwithMBBHIGH.TheMail2Register  
Flag(MBF2)issetHIGHbyaLOW-to-HIGHtransitiononCLKAwhenaport  
A read is selected by CSA, W/RA, and ENA and with MBA HIGH. The data  
inamailregisterremainsintactafteritisreadandchangesonlywhennewdata  
iswrittentotheregister.FormailregisterandMailRegisterFlagtimingdiagrams,  
see Figure 20 and 21.  
ALMOST-FULL FLAGS (AFA, AFB)  
TheAlmost-FullflagofaFIFOissynchronizedtotheportclockthatwrites  
datatoitsarray.ThestatemachinethatcontrolsanAlmost-Fullflagmonitorsa  
writepointerandreadpointercomparatorthatindicateswhentheFIFOmemory  
statusisalmost-full,almost-full-1,oralmost-full-2.Thealmost-fullstateisdefined  
13  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
CLKA  
CLKB  
t
RSTH  
t
RSTS  
t
FSS  
t
FSH  
RST1  
FWFT  
tFWS  
0,1  
FS1,FS0  
FFA/IRA  
t
WFF  
t
WFF  
t
REF  
EFB/ORB  
AEB  
t
t
RSF  
RSF  
AFA  
t
RSF  
MBF1  
4660 drw 04  
NOTES:  
1. FIFO2 is reset in the same manner to load X2 and Y2 with a preset value.  
2. If FWFT is HIGH, then EFB/ORB will go LOW one CLKB cycle earlier than in this case where FWFT is LOW.  
Figure 2. FIFO1 Reset and Loading X1 and Y1 with a Preset Value of Eight(1) (IDT Standard and FWFT Modes)  
CLKA  
4
1
2
tFSS  
RST1,  
RST2  
tFSH  
0,0  
FS1,FS0  
tWFF  
FFA/IRA  
ENA  
(1)  
tENS2  
tSKEW1  
tENH  
tDH  
tDS  
A0 - A35  
First Word to FIFO1  
AFA Offset  
AEB Offset  
(X1)  
AFB Offset  
AEA Offset  
(Y1)  
(Y2)  
(X2)  
CLKB  
1
2
tWFF  
FFB/IRB  
4660 drw 05  
NOTES:  
1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKB edge for FFB/IRB to transition HIGH in the next cycle. If the time between the rising edge of CLKA and rising  
edge of CLKB is less than tSKEW1, then FFB/IRB may transition HIGH one CLKB cycle later than shown.  
2. CSA = LOW, W/RA = HIGH, MBA = LOW. It is not necessary to program offset register on consecutive clock cycles.  
Figure 3. Parallel Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes)  
14  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKL  
tCLKH  
CLKA  
FFA/IRA  
HIGH  
tENS1  
tENH  
CSA  
t
ENS2  
ENS2  
t
ENH  
ENH  
ENH  
W/RA  
MBA  
ENA  
t
t
tENS2  
t
ENS2  
tENS2  
t
tENH  
tENH  
tDH  
tDS  
W1(1)  
W2(1)  
No Operation  
A0 - A35  
4660 drw 06  
NOTE:  
1. Written to FIFO1.  
Figure 4. Port A Write Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)  
tCLK  
tCLKH  
tCLKL  
CLKB  
FFB/IRB HIGH  
tENH  
tENH  
tENS1  
CSB  
tENS2  
W/RB  
tENH  
tENH  
tENS2  
tENS2  
MBB  
tENH  
tENH  
tENS2  
tENS2  
ENB  
tDH  
tDS  
(1)  
W2(1)  
No Operation  
B0 - B35  
W1  
4660 drw 07  
NOTE:  
1. Written to FIFO2.  
Figure 5. Port B Write Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)  
15  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKH  
tCLKL  
CLKB  
EFB/ORB HIGH  
CSB  
W/RB  
tENS2  
MBB  
tENH  
tENH  
tENH  
tENS2  
tENS2  
ENB  
No Operation  
W2(1)  
t
DIS  
DIS  
t
t
MDV  
MDV  
t
A
t
A
A
t
EN  
EN  
B0-B35  
Previous Data  
W1(1)  
W2(1)  
(IDT Standard Mode)  
t
OR  
tA  
t
t
B0-B35  
W1(1)  
W3 (1)  
(FWFT Mode)  
4660 drw 08  
NOTE:  
1. Read From FIFO1.  
Figure 6. Port B Read Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)  
tCLK  
tCLKH  
tCLKL  
CLKA  
EFA/ORA HIGH  
CSA  
W/RA  
MBA  
ENA  
t
ENS2  
t
ENH  
tENH  
t
ENH  
t
ENS2  
t
ENS2  
t
DMV  
No Operation  
W2(1)  
t
DIS  
DIS  
t
A
t
A
t
EN  
A0-A35  
Previous Data  
W1(1)  
W2(1)  
(Standard Mode)  
t
t
MDV  
t
A
OR  
tA  
t
EN  
A0-A35  
W3(1)  
W1(1)  
(FWFT Mode)  
4660 drw 09  
NOTE:  
1. Read From FIFO2.  
Figure 7. Port A Read Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)  
16  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
t
CLK  
t
CLKL  
tCLKH  
CLKA  
CSA  
LOW  
HIGH  
WRA  
tENS2  
tENH  
MBA  
tENS2  
tENH  
ENA  
HIGH  
IRA  
tDH  
tDS  
A0 - A35  
W1  
t
CLK  
(1)  
tSKEW1  
tCLKH  
tCLKL  
1
2
3
CLKB  
t
REF  
t
REF  
ORB FIFO1Empty  
CSB LOW  
W/RB  
HIGH  
LOW  
MBB  
tENS2  
tENH  
ENB  
tA  
B0- B35  
Old Data in FIFO1 Output Register  
W1  
4660 drw 10  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for ORB to transition HIGH and to clock the next word to the FIFO1 output register in three CLKB cycles.  
If the time between the rising CLKA edge and rising CLKB edge is less than tSKEW1, then the transition of ORB HIGH and load of the first word to the output register may occur one CLKB  
cycle later than shown.  
Figure 8. ORB Flag Timing and First Data Word Fall Through when FIFO1 is Empty (FWFT Mode)  
17  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
t
CLK  
t
CLKL  
tCLKH  
CLKA  
CSA  
LOW  
HIGH  
WRA  
t
ENS2  
t
ENH  
ENH  
MBA  
tENS2  
t
ENA  
FFA  
HIGH  
tDS  
tDH  
A0-A35  
W1  
t
CLKtCLKL  
(1)  
SKEW1  
t
CLKH  
t
CLKB  
1
2
t
REF  
tREF  
FIFO1 Empty  
LOW  
EFB  
CSB  
W/RB  
HIGH  
LOW  
MBB  
tENH  
tENS2  
ENB  
tA  
W1  
B0-B35  
4660 drw 11  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for EFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and rising  
CLKB edge is less than tSKEW1, then the transition of EFB HIGH may occur one CLKB cycle later than shown.  
Figure 9. EFB Flag Timing and First Data Read Fall Through when FIFO1 is Empty (IDT Standard Mode)  
18  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKL  
tCLKH  
CLKB  
LOW  
LOW  
CSB  
W/RB  
tENS2  
tENH  
MBB  
ENB  
tENS2  
tENH  
IRB  
HIGH  
tDS  
tDH  
B0 - B35  
W1  
t
CLK  
(1)  
SKEW1  
t
tCLKH  
t
CLKL  
1
2
3
CLKA  
ORA  
t
REF  
t
REF  
FIFO2 Empty  
LOW  
LOW  
LOW  
CSA  
W/RA  
MBA  
tENS2  
tENH  
ENA  
tA  
Old Data in FIFO2 Output Register  
W1  
A0- A35  
4660 drw 12  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for ORA to transition HIGH and to clock the next word to the FIFO2 output register in three CLKA cycles.  
If the time between the rising CLKB edge and rising CLKA edge is less than tSKEW1, then the transition of ORA HIGH and load of the first word to the output register may occur one CLKA  
cycle later than shown.  
Figure 10. ORA Flag Timing and First Data Word Fall Through when FIFO2 is Empty (FWFT Mode)  
19  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
t
CLK  
t
CLKH  
tCLKL  
CLKB  
LOW  
LOW  
CSB  
W/RB  
t
ENS2  
ENS2  
t
ENH  
MBB  
ENB  
t
t
ENH  
HIGH  
FFB  
tDH  
tDS  
W1  
B0-B35  
t
CLK  
(1)  
SKEW1  
t
CLKH  
t
tCLKL  
1
2
CLKA  
t
REF  
t
REF  
EFA  
FIFO2 Empty  
LOW  
LOW  
CSA  
W/RA  
MBA  
LOW  
tENS2  
tENH  
ENA  
tA  
A0-A35  
W1  
4660 drw 13  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for EFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and rising  
CLKA edge is less than tSKEW1, then the transition of EFA HIGH may occur one CLKA cycle later than shown.  
Figure 11. EFA Flag Timing and First Data Read when FIFO2 is Empty (IDT Standard Mode)  
20  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKH  
tCLKL  
CLKB  
LOW  
CSB  
W/RB  
HIGH  
LOW  
MBB  
tENH  
tENS2  
ENB  
HIGH  
ORB  
tA  
Previous Word in FIFO1 Output Register  
SKEW1  
Next Word From FIFO1  
B0- B35  
(1)  
t
tCLK  
tCLKH  
tCLKL  
1
2
CLKA  
tWEF  
tWEF  
FIFO1 Full  
LOW  
IRA  
CSA  
W/RA  
HIGH  
tENS2  
tENH  
MBA  
tENS2  
tENH  
ENA  
A0 - A35  
NOTE:  
tDS  
tDH  
Write  
4660 drw 14  
To FIFO1  
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for IRA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and rising  
CLKA edge is less than tSKEW1, then IRA may transition HIGH one CLKA cycle later than shown.  
Figure 12. IRA Flag Timing and First Available Write when FIFO1 is Full (FWFT Mode)  
21  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKH  
tCLKL  
CLKB  
LOW  
CSB  
W/RB  
MBB  
HIGH  
LOW  
tENS2  
tENH  
ENB  
EFB  
HIGH  
tA  
Previous Word in FIFO1 Output Register  
Next Word From FIFO1  
B0-B35  
(1)  
tSKEW1  
tCLK  
tCLKH  
tCLKL  
CLKA  
1
2
t
WFF  
t
WFF  
FIFO1 Full  
LOW  
FFA  
CSA  
HIGH  
W/RA  
t
ENS2  
t
ENH  
ENH  
MBA  
t
ENS2  
t
ENA  
tDH  
tDS  
A0-A35  
Write  
4660 drw 15  
To FIFO1  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for FFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and rising  
CLKA edge is less than tSKEW1, then FFA may transition HIGH one CLKA cycle later than shown.  
Figure 13. FFA Flag Timing and First Available Write when FIFO1 is Full (IDT Standard Mode)  
22  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKH  
tCLKL  
CLKA  
LOW  
CSA  
W/RA LOW  
LOW  
MBA  
ENA  
tENS2  
tENH  
HIGH  
ORA  
tA  
Previous Word in FIFO2 Output Register  
SKEW1  
Next Word From FIFO2  
A0- A35  
(1)  
t
tCLK  
tCLKH  
tCLKL  
1
2
CLKB  
IRB  
tWEF  
tWEF  
FIFO2 FULL  
LOW  
CSB  
LOW  
W/RB  
tENS2  
tENH  
MBB  
ENB  
tENS2  
tENH  
tDS  
tDH  
Write  
B0 - B35  
4660 drw 16  
To FIFO2  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for IRB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and rising  
CLKB edge is less than tSKEW1, then IRB may transition HIGH one CLKB cycle later than shown.  
Figure 14. IRB Flag Timing and First Available Write when FIFO2 is Full (FWFT Mode)  
23  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
tCLK  
tCLKH  
tCLKL  
CLKA  
LOW  
LOW  
LOW  
CSA  
W/RA  
MBA  
tENS2  
tENH  
ENA  
EFA  
HIGH  
tA  
Previous Word in FIFO2 Output Register  
Next Word From FIFO2  
A0-A35  
(1)  
tCLK  
tSKEW1  
tCLKH  
tCLKL  
CLKB  
1
2
t
WFF  
t
WFF  
FIFO2 Full  
LOW  
FFB  
CSB  
W/RB LOW  
tENH  
tENS2  
MBB  
ENB  
t
ENS2  
t
ENH  
tDS  
tDH  
Write  
B0-B35  
4660 drw 17  
To FIFO2  
NOTE:  
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for FFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and rising  
CLKB edge is less than tSKEW1, then FFB may transition HIGH one CLKB cycle later than shown.  
Figure 15. FFB Flag Timing and First Available Write when FIFO2 is Full (IDT Standard Mode)  
CLKA  
tENS2  
tENH  
ENA  
(1)  
SKEW2  
t
1
2
CLKB  
t
PAE  
t
PAE  
AEB  
X1 Words in FIFO1  
(X1+1) Words in FIFO1  
ENS2  
t
tENH  
ENB  
4660 drw 18  
NOTES:  
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for AEB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA edge and rising  
CLKB edge is less than tSKEW2, then AEB may transition HIGH one CLKB cycle later than shown.  
2. FIFO1 Write (CSA = LOW, W/RA = LOW, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = HIGH, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO.  
Figure 16. Timing for AEB when FIFO1 is Almost-Empty (IDT Standard and FWFT Modes)  
24  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
CLKB  
tENS2  
tENH  
ENB  
(1)  
tSKEW2  
1
CLKA  
2
t
PAE  
t
PAE  
AEA  
X2 Words in FIFO2  
(X2+1) Words in FIFO2  
ENS2  
t
tENH  
ENA  
4660 drw 19  
NOTES:  
1. tSKEW2 is the minimum time between a rising CLKB edge and a rising CLKA edge for AEA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and rising  
CLKA edge is less than tSKEW2, then AEA may transition HIGH one CLKA cycle later than shown.  
2. FIFO2 Write (CSB = LOW, W/RB = LOW, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO.  
Figure 17. Timing for AEA when FIFO2 is Almost-Empty (IDT Standard and FWFT Modes)  
(1)  
SKEW2  
t
1
2
t
CLKA  
ENA  
tENS2  
tENH  
PAF  
t
PAF  
(D-Y1) Words in FIFO1  
[D-(Y1+1)] Words in FIFO1  
AFA  
CLKB  
tENS2  
tENH  
ENB  
4660 drw 20  
NOTES:  
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for AFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKA edge and rising  
CLKB edge is less than tSKEW2, then AFA may transition HIGH one CLKA cycle later than shown.  
2. FIFO1 Write (CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = HIGH, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO.  
3. D = Maximum FIFO Depth = 256 for the IDT72V3622, 512 for the IDT72V3632, 1,024 for the IDT72V3642.  
Figure 18. Timing for AFA when FIFO1 is Almost-Full (IDT Standard and FWFT Modes)  
25  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
(1)  
SKEW2  
t
1
2
CLKB  
tENS2  
tENH  
ENB  
AFB  
t
PAF  
tPAF  
(D-Y2) Words in FIFO2  
[D-(Y2+1)] Words in FIFO2  
CLKA  
tENH  
tENS2  
ENA  
4660 drw 21  
NOTES:  
1. tSKEW2 is the minimum time between a rising CLKB edge and a rising CLKA edge for AFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKB edge and rising  
CLKA edge is less than tSKEW2, then AFB may transition HIGH one CLKB cycle later than shown.  
2. FIFO2 write (CSB = LOW, W/RB = LOW, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO.  
3. D = Maximum FIFO Depth = 256 for the IDT72V3622, 512 for the IDT72V3632, 1,024 for the IDT72V3642.  
Figure 19. Timing for AFB when FIFO2 is Almost-Full (IDT Standard and FWFT Modes)  
CLKA  
tENH  
tENS1  
CSA  
W/RA  
MBA  
t
ENH  
t
ENS1  
t
ENH  
t
ENS2  
tENH  
tENS2  
ENA  
A0 - A35  
CLKB  
tDH  
t
DS  
W1  
t
PMF  
tPMF  
MBF1  
CSB  
W/RB  
MBB  
ENB  
tENH  
tENS2  
t
MDV  
tEN  
t
PMR  
tDIS  
FIFO1 Output Register  
W1 (Remains valid in Mail1 Register after read)  
B0 - B35  
4660 drw 22  
Figure 20. Timing for Mail1 Register and MBF1 Flag (IDT Standard and FWFT Modes)  
26  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
CLKB  
tENS1  
tENH  
CSB  
W/RB  
MBB  
ENB  
t
ENS1  
ENS2  
t
ENH  
t
t
ENH  
tENS2  
t
t
ENH  
DH  
tDS  
W1  
B0-B35  
CLKA  
t
PMF  
tPMF  
MBF2  
CSA  
W/RA  
MBA  
ENA  
tENH  
tENS2  
t
PMR  
tEN  
tDIS  
t
MDV  
W1 (Remains valid in Mail 2 Register after read)  
A0-A35  
4660 drw23  
FIFO2 Output Register  
Figure 21. Timing for Mail2 Register and MBF2 Flag (IDT Standard and FWFT Modes)  
27  
IDT72V3622/72V3632/72V3642 CMOS 3.3V SyncBiFIFOTM  
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2  
COMMERCIAL TEMPERATURERANGE  
PARAMETER MEASUREMENT INFORMATION  
3.3V  
Ω
330  
From Output  
Under Test  
30 pF (1)  
Ω
510  
PROPAGATION DELAY  
LOAD CIRCUIT  
3V  
3V  
Timing  
Input  
1.5V  
High-Level  
1.5V  
Input  
1.5V  
GND  
GND  
3V  
t
S
th  
t
W
3V  
Data,  
Enable  
Input  
1.5V  
1.5V  
Low-Level  
1.5V  
1.5V  
GND  
Input  
GND  
VOLTAGE WAVEFORMS  
SETUP AND HOLD TIMES  
VOLTAGE WAVEFORMS  
PULSE DURATIONS  
3V  
Output  
Enable  
1.5V  
1.5V  
t
PZL  
GND  
tPLZ  
3V  
3V  
Input  
1.5V  
1.5V  
1.5V  
Low-Level  
Output  
GND  
V
OL  
tPD  
t
PZH  
tPD  
V
OH  
V
OH  
In-Phase  
Output  
1.5V  
1.5V  
High-Level  
Output  
1.5V  
t
PHZ  
V
OL  
OV  
VOLTAGE WAVEFORMS  
ENABLE AND DISABLE TIMES  
VOLTAGE WAVEFORMS  
PROPAGATION DELAY TIMES  
4660 drw 24  
NOTE:  
1. Includes probe and jig capacitance.  
Figure 22. Load Circuit and Voltage Waveforms  
28  
ORDERING INFORMATION  
X
XXXXXX  
X
XX  
X
X
X
Device Type Power  
Speed  
Package  
Process/  
Temperature  
Range  
BLANK  
8
Tube or Tray  
Tape and Reel  
BLANK  
G
Commercial (0°C to +70°C)  
Green  
PF  
Thin Quad Flat Pack (TQFP, PN120-1)  
10  
15  
Clock Cycle Time (tCLK  
)
Commercial Only  
Low Power  
Speed in Nanoseconds  
L
72V3622  
72V3632  
72V3642  
256 x 36 x 2 3.3V SyncBiFIFO  
512 x 36 x 2 3.3V SyncBiFIFO  
1,024 x 36 x 2 3.3V SyncBiFIFO  
4660 drw 25  
NOTE:  
1. Industrial temperature range is available by special order.  
DATASHEETDOCUMENTHISTORY  
12/19/2000  
03/21/2001  
08/01/2001  
12/18/2001  
02/10/2009  
05/09/2013  
05/15/2013  
pg. 11.  
pgs. 6 and 7.  
pgs. 6, 8, 9 and 29.  
pg. 27.  
pgs. 1 and 29.  
pgs. 1-3, 6, 8, 9 and 29.  
pg. 29.  
CORPORATE HEADQUARTERS  
6024 Silver Creek Valley Road  
San Jose, CA 95138  
for SALES:  
for Tech Support:  
408-360-1753  
email:FIFOhelp@idt.com  
800-345-7015 or 408-284-8200  
fax: 408-284-2775  
www.idt.com  
29  

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