33
COMMERCIAL TEMPERATURE RANGE
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFO
TM
WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2 and 8,192 x 36 x 2
NOTES:
1. tSKEW2 is the minimum time between a rising CLKC edge and a rising CLKA edge for AFC to transition HIGH in the next CLKC cycle. If the time between the rising CLKC edge and rising
CLKA edge is less than tSKEW2, then AFC may transition HIGH one CLKC cycle later than shown.
2. FIFO2 write (MBC = 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 = 2,048 for the IDT72V3656, 4,096 for the IDT72V3666, 8,192 for the IDT72V3676.
4. Port C size is word or byte, AFC is set LOW by the last word or byte write of the long word, respectively.
Figure 27. Timing for
AFCAFC
AFCAFC
AFC
when FIFO2 is Almost-Full (IDT Standard and FWFT Modes)
Figure 25. Timing for
AEAAEA
AEAAEA
AEA
when FIFO2 is Almost-Empty (IDT Standard and FWFT Modes)
Figure 26. Timing for
AFAAFA
AFAAFA
AFA
when FIFO1 is Almost-Full (IDT Standard and FWFT Modes)
NOTES:
1. tSKEW2 is the minimum time between a rising CLKC edge and a rising CLKA edge for AEA to transition HIGH in the next CLKA cycle. If the time between the rising CLKC edge and rising
CLKA edge is less than tSKEW2, then AEA may transition HIGH one CLKA cycle later than shown.
2. FIFO2 Write (MBC = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO.
3. If Port C size is word or byte, tSKEW2 is referenced to the rising CLKC edge that writes the last word or byte of the long word, respectively.
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, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO.
3. D = Maximum FIFO Depth = 2,048 for the IDT72V3656, 4,096 for the IDT72V3666, 8,192 for the IDT72V3676.
4. If Port B size is word or byte, tSKEW2 is referenced from the rising CLKB edge that reads the last word or byte of the long word, respectively.
AEA
CLKC
ENA
4665 drw 26
WENC
CLKA
2
1
t
ENS2
t
ENH
t
SKEW2
t
PAE
t
PAE
t
ENS2
t
ENH
(X2+1) Words in FIFO2
X2 Words in FIFO2
(1)
AFA
CLKA
RENB
4665 drw 27
ENA
CLKB
12
t
SKEW2
t
ENS2
t
ENH
t
PAF
t
ENS2
t
ENH
t
PAF
[D-(Y1+1)] Words in FIFO1
(D-Y1) Words in FIFO1
(1)
AFC
CLKC
ENA
4665 drw 28
WENC
CLKA
12
t
SKEW2
t
ENS2
t
ENH
t
PAF
t
ENS2
t
ENH
t
PAF
[D-(Y2+1)] Words in FIFO2
(D-Y2) Words in FIFO2
(1)
