COMMERCIALANDINDUSTRIAL
TEMPERATURERANGES
IDT72805LB/72815LB/72825LB/72835LB/72845LB CMOS Dual SyncFIFOTM
256 x 18, 512 x 18, 1,024 x 18, 2,048 x 18 and 4,096 x 18
16
JANUARY 13, 2009
Figure 15. Half-Full Flag Timing (IDT Standard and FWFT Modes)
Figure 14. Asynchronous Programmable Almost-Full Flag Timing (IDT Standard and FWFT Modes)
NOTES:
1. m =
PAF offset.
2. D = maximum FIFO Depth.
In IDT Standard Mode: D = 256 for the IDT72805, 512 for the IDT72815, 1,024 for the IDT72825, 2,048 for the IDT72835 and 4,096 for the IDT72845.
In FWFT Mode: D = 257 for the IDT72805, 513 for the IDT72815, 1,025 for the IDT72825, 2,049 for the IDT72835 and 4,097 for the IDT72845.
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.
NOTES:
1. D = maximum FIFO Depth.
In IDT Standard Mode: D = 256 for the IDT72805, 512 for the IDT72815, 1,024 for the IDT72825, 2,048 for the IDT72835 and 4,096 for the IDT72845.
In FWFT Mode: D = 257 for the IDT72805, 513 for the IDT72815, 1,025 for the IDT72825, 2,049 for the IDT72835 and 4,097 for the IDT72845.
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
tCLKH
tCLKL
tENS
tENH
WEN
PAF
tENS
tPAFA
D - (m + 1) words in FIFO
RCLK
tPAFA
REN
(1)
3139 drw 14
D - m words in FIFO
D - (m + 1) words in FIFO
WCLK
tENS
tENH
WEN
HF
tENS
tHF
RCLK
tHF
REN
3139 drw 15
tCLKL
tCLKH
D/2 words in FIFO(2),
[
+ 1
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
D-1
2