43
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72T1845/55/65/75/85/95/105/115/125 2.5V TeraSync™ 18-BIT/9-BIT FIFO
2Kx18/4Kx9, 4Kx18/
8Kx9, 8Kx18/16Kx9, 16Kx18/32Kx9, 32Kx18/64Kx9, 64Kx18/128Kx9, 128Kx18/256Kx9, 256Kx18/512Kx9, 512Kx18/1Mx9
FEBRUARY 10, 2009
Figure 19. Retransmit from Mark (First Word Fall Through Mode)
t
REF
t
ENS
t
ENH
5909 drw23
t
ENS
W
MK-1
WCLK
RCLK
REN
RT
OR
PAF
HF
PAE
Q
n
12
1
t
PAFS
t
REF
2
WEN
t
ENS
t
A
t
ENS
W
MK
W
MK+1
t
A
t
A
W
MK+n
t
A
W
MK+1
W
MK+2
t
A
t
ENS
MARK
t
ENH
t
ENS
t
PAES
(6)
t
A
t
SKEW2
t
HF
W
MK
t
A
3
NOTES:
1. Retransmit setup is complete when OR returns LOW.
2. OE = LOW;RCS = LOW.
3. RT must be HIGH when reading from FIFO.
4. Once Mark is set, the write pointer will not increment past the ‘marked’ location, preventing overwrites of Retransmit data.
5. Before a “MARK” can be set there must be at least 32 bytes of data between the Write Pointer and Read Pointer locations for the IDT72T1845/72T1855/72T1865/72T1875/72T1885/72T1895, 64 bytes of data for the IDT72T18105/
72T18115 and 128 bytes of data for the IDT72T18125. (32 bytes = 16 words = 8 long words).
6. A transition in the PAE flag may occur one RCLK cycle earlier than shown, (on cycle 2).
44
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72T1845/55/65/75/85/95/105/115/125 2.5V TeraSync™ 18-BIT/9-BIT FIFO
2Kx18/4Kx9, 4Kx18/
8Kx9, 8Kx18/16Kx9, 16Kx18/32Kx9, 32Kx18/64Kx9, 64Kx18/128Kx9, 128Kx18/256Kx9, 256Kx18/512Kx9, 512Kx18/1Mx9
FEBRUARY 10, 2009
Figure 20. Serial Loading of Programmable Flag Registers (IDT Standard and FWFT Modes)
NOTES:
1. x9 to x9 mode: X =12 for the IDT72T1845, X = 13 for the IDT72T1855, X = 14 for the IDT72T1865, X = 15 for the IDT72T1875, X = 16 for the IDT72T1885, X = 17 for the IDT72T1895,
X = 18 for the IDT72T18105, X = 19 for the IDT72T18115 and X = 20 for the IDT72T18125.
2. All other modes: X=11 for the IDT72T1845, X = 12 for the IDT72T1855, X = 13 for the IDT72T1865, X = 14 for the IDT72T1875, X = 15 for the IDT72T1885 and X = 16 for the IDT72T1895,
X = 17 for the IDT72T18105, X = 18 for the IDT72T18115 and X = 19 for the IDT72T18125.
SCLK
SEN
SI
5909 drw24
LD
EMPTY OFFSET
FULL OFFSET
BIT X
(1)
tSENS
tLDS
tSDS
tSENH
tLDS
BIT X
(1)
BIT 1
tENH
tLDH
tSDH
tSCLK
tSCKH tSCKL
BIT 1
NOTES:
1. OE = LOW.
2. The timing diagram illustrates reading of offset registers with an output bus width of 18 bits.
3. The offset registers cannot be read on consecutive RCLK cycles. The read must be disabled (REN = HIGH) for a minimum of one RCLK cycle in between register accesses.
Figure 22. Parallel Read of Programmable Flag Registers (IDT Standard and FWFT Modes)
Figure 21. Parallel Loading of Programmable Flag Registers (IDT Standard and FWFT Modes)
NOTES:
1. This timing diagram is based on programming with a x18 bus width.
2. Overwrites previous offset value.
WCLK
LD
WEN
D
0
- D
17
5909 drw25
t
LDS
t
ENS
PAE OFFSET
t
DS
t
DH
t
LDH
t
ENH
t
CLK
t
CLKH
t
CLKL
PAF OFFSET
PAE
(2)
OFFSET
PAF
(2)
OFFSET
t
DH
t
DH
t
DH
t
DS
t
DS
t
DS
t
LDH
t
ENH
RCLK
LD
REN
Q
0
- Q
17
DATA IN OUTPUT REGISTER PAE OFFSET VALUE PAF OFFSET VALUE
5909 drw26
t
LDH
t
ENH
t
CLK
t
CLKL
t
CLKH
t
A
t
LDS
t
LDH
t
LDS
t
LDH
t
LDS
t
ENS
t
ENH
t
ENS
t
ENH
t
ENS
t
A
PAE OFFSET
t
A
45
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72T1845/55/65/75/85/95/105/115/125 2.5V TeraSync™ 18-BIT/9-BIT FIFO
2Kx18/4Kx9, 4Kx18/
8Kx9, 8Kx18/16Kx9, 16Kx18/32Kx9, 32Kx18/64Kx9, 64Kx18/128Kx9, 128Kx18/256Kx9, 256Kx18/512Kx9, 512Kx18/1Mx9
FEBRUARY 10, 2009
NOTES:
1. m = PAF offset .
2. D = maximum FIFO depth.
In IDT Standard mode: if x18 Input or x18 Output bus Width is selected, D = 2,048 for the IDT72T1845, 4,096 for the IDT72T1855, 8,192 for the IDT72T1865, 16,384 for the IDT72T1875,
32,768 for the IDT72T1885, 65,536 for the IDT72T1895, 131,072 for the IDT72T18105, 262,144 for the IDT72T18115 and 524,288 for the IDT72T18125. If both x9 Input and x9
Output bus Widths are selected, D = 4,096 for the IDT72T1845, 8,192 for the IDT72T1855, 16,384 for the IDT72T1865, 32,768 for the IDT72T1875, 65,536 for the IDT72T1885,
131,072 for the IDT72T1895, 262,144 for the IDT72T18105, 524,288 for the IDT72T18115 and 1,048,576 for the IDT72T18125.
In FWFT mode: if x18 Input or x18 Output bus Width is selected, D = 2,049 for the IDT72T1845, 4,097 for the IDT72T1855, 8,193 for the IDT72T1865, 16,385 for the IDT72T1875,
32,769 for the IDT72T1885, 65,537 for the IDT72T1895, 131,073 for the IDT72T18105, 262,145 for the IDT72T18115 and 524,289 for the IDT72T18125. If both x9 Input and x9
Output bus Widths are selected, D = 4,097 for the IDT72T1845, 8,193 for the IDT72T1855, 16,385 for the IDT72T1865, 32,769 for the IDT72T1875, 65,537 for the IDT72T1885,
131,073 for the IDT72T1895, 262,145 for the IDT72T18105, 524,289 for the IDT72T18115 and 1,048,577 for the IDT72T18125.
3. tSKEW2 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 tPAFS). If the time between the
rising edge of RCLK and the rising edge of WCLK is less than tSKEW2, 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.
6. RCS is LOW.
Figure 23. Synchronous Programmable Almost-Full Flag Timing (IDT Standard and FWFT Modes)
WCLK
WEN
PAF
RCLK
REN
5909 drw27
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
SKEW2
(3)
t
PAFS
t
CLKL
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
5909 drw28
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

72T1895L4-4BBI

Mfr. #:
Manufacturer:
Description:
IC FIFO 65536X18 4NS 144BGA
Lifecycle:
New from this manufacturer.
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