43
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72T7285/72T7295/72T72105/72T72115 2.5V TeraSync
™™
™™
™ 72-BIT FIFO
16,384 x 72, 32,768 x 72, 65,536 x 72, 131,072 x 72
NOTES:
1. m = PAF offset.
2. D = maximum FIFO depth.
In IDT Standard mode: D = 16,384 for the IDT72T7285, 32,768 for the IDT72T7295, 65,536 for the IDT72T72105 and 131,072 for the IDT72T72115.
In FWFT mode: D = 16,385 for the IDT72T7285, 32,769 for the IDT72T7295, 65,537 for the IDT72T72105 and 131,073 for the IDT72T72115.
3.
t
SKEW2
is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that PAF will go HIGH (after one WCLK cycle plus t
PAFS
). If the time between the
rising edge of RCLK and the rising edge of WCLK is less than t
SKEW2
, then the PAF deassertion time may be delayed one extra WCLK cycle.
4. PAF is asserted and updated on the rising edge of WCLK only.
5. Select this mode by setting PFM HIGH during Master Reset.
Figure 23. Synchronous Programmable Almost-Full Flag Timing (IDT Standard and FWFT Modes)
WCLK
WEN
PAF
RCLK
REN
5994 drw28
1
2
12
D-(m+1) words
in FIFO
(2)
D - m words in FIFO
(2)
D - (m +1) words in FIFO
(2)
t
ENH
t
ENS
t
PAFS
t
ENS
t
ENH
t
CLKL
t
CLKL
t
SKEW2
(3)
t
PAFS
NOTES:
1. n = PAE offset.
2. For IDT Standard mode
3. For FWFT mode.
4.
tSKEW2 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that PAE will go HIGH (after one RCLK cycle plus tPAES). If the time between the
rising edge of WCLK and the rising edge of RCLK is less than tSKEW2, then the PAE deassertion may be delayed one extra RCLK cycle.
5. PAE is asserted and updated on the rising edge of WCLK only.
6. Select this mode by setting PFM HIGH during Master Reset.
7. RCS = LOW.
Figure 24. Synchronous Programmable Almost-Empty Flag Timing (IDT Standard and FWFT Modes)
WCLK
WEN
PAE
RCLK
12 12
REN
5994 drw29
n + 1 words in FIFO
(2)
,
n + 2 words in FIFO
(3)
t
ENS
t
SKEW2
(4)
t
ENH
t
PAES
n words in FIFO
(2)
,
n + 1 words in FIFO
(3)
t
PAES
n words in FIFO
(2)
,
n + 1 words in FIFO
(3)
t
ENS
t
ENH
t
CLKH
t
CLKL
