24
COMMERCIALTEMPERATURERANGE
IDT723653/723663/723673 CMOS SyncFIFOTM WITH BUS-MATCHING
2,048 x 36 x 2, 4,096 x 36 x 2 and 8,192 x 36 x 2
NOTES:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for
FF 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
FF may transition HIGH one CLKA cycle later than shown.
2. If Port B size is word or byte, tSKEW1 is referenced from the rising CLKB edge that reads the last word or byte of the long word, respectively.
Figure 14.
FF
FF Flag Timing and First Available Write when FIFO is Full (IDT Standard Mode)
NOTES:
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for
AE 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
AE may transition HIGH one CLKB cycle later than shown.
2. FIFO Write (
CSA = LOW, W/RA = LOW, MBA = LOW), FIFO read (CSB = LOW, W/RB = HIGH, MBB = LOW). Data in the FIFO output register has been read from the FIFO.
3. If Port B size is word or byte,
AE is set LOW by the last word or byte read from the FIFO, respectively.
Figure 15. Timing for
AE
AE when the FIFO is Almost-Empty (IDT Standard and FWFT Modes).
CSB
EF
W/RB
MBB
ENB
B0-B35
CLKB
FF
CLKA
CSA
5610 drw16
W/RA
A0-A35
MBA
ENA
12
tCLK
tCLKH
tCLKL
tENS2
tENH
tA
tSKEW1
tCLK
tCLKL
tENS2
tDS
tENH
tDH
To FIFO
Previous Word in FIFO Output Register
Next Word From FIFO
LOW
HIGH
LOW
HIGH
LOW
HIGH
(1)
FIFO Full
WFF
t
tCLKH
AE
CLKA
ENB
5610 drw17
ENA
CLKB
2
1
tENS2
tENH
tSKEW2
tPAE
tENS2
tENH
X Words in FIFO
(X+1) Words in FIFO
(1)