16
IDT72V805/72V815/72V825/72V835/72V845
3.3 V CMOS DUAL SyncFIFO™ 256 x 18, 512 x 18, 1,024 x 18, 4,096 x 18
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
NOTES:
1. D = maximum FIFO Depth.
In IDT Standard Mode: D = 256 for the IDT72V805, 512 for the IDT72V815, 1,024 for the IDT72V825, 2,048 for the IDT72V835 and 4,096 for the IDT72V845. In FWFT Mode:
D = 257 for the IDT72V805, 513 for the IDT72V815, 1,025 for the IDT72V825, 2,049 for the IDT72V835 and 4,097 for the IDT72V845.
2. For IDT Standard Mode.
3. For FWFT Mode.
4. Select this mode by setting (FL, RXI, WXI) = (0,0,0), (0,0,1), (0,1,0), (1,0,0), (1,0,1) or (1,1,0) during Reset.
WCLK
t
ENS
t
ENH
WEN
HF
t
ENS
RCLK
REN
4295 drw 15
D/2 words in FIFO
(2)
,
[ + 1] words in FIFO
(3)
D-1
2
D/2 + 1 words in FIFO
(2)
,
[ + 2] words in FIFO
(3)
D-1
2
D/2 words in FIFO
(2)
,
[ + 1] words in FIFO
(3)
D-1
2
t
HF
t
HF
t
CLKL
t
CLKH
NOTES:
1. m = PAF offset.
2. D = maximum FIFO Depth.
In IDT Standard Mode: D = 256 for the IDT72V805, 512 for the IDT72V815, 1,024 for the IDT72V825, 2,048 for the IDT72V835 and 4,096 for the IDT72V845. In FWFT Mode:
D = 257 for the IDT72V805, 513 for the IDT72V815, 1,025 for the IDT72V825, 2,049 for the IDT72V835 and 4,097 for the IDT72V845.
3. PAF is asserted to LOW on WCLK transition and reset to HIGH on RCLK transition.
4. Select this mode by setting (FL, RXI, WXI) = (0,0,0), (0,0,1), (0,1,0), (0,1,1) or (1,1,1) during Reset.
WCLK
t
CLKH
t
CLKL
t
ENS
t
ENH
WEN
PAF
t
ENS
t
PAFA
D - (m + 1) words
in FIFO
RCLK
t
PAFA
REN
(1)
4295 drw 14
D - m words
in FIFO
D - (m + 1) words in FIFO
Figure 14. Asynchronous Programmable Almost-Full Flag Timing (IDT Standard and FWFT Modes)
Figure 15. Half-Full Flag Timing (IDT Standard and FWFT Modes)
