22
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72V223/233/243/253/263/273/283/293 3.3V HIGH DENSITY SUPERSYNC IITM NARROW BUS FIFO
512 x 18, 1K x 9/18, 2K x 9/18, 4K x 9/18, 8K x 9/18, 16K x 9/18, 32K x 9/18, 64K x 9/18, 128K x 9
FEBRUARY 11, 2009
IDT72V263, (32,768-m) writes for the IDT72V273, (65,536-m) writes for the
IDT72V283 and (131,072-m) writes for the IDT72V293. The offset “m” is the
full offset value. The default setting for this value is stated in Table 2.
In FWFT mode, if x18 Input or x18 Output bus Width is selected, the
PAF
will go LOW after (513-m) writes for the IDT72V223, (1,025-m) writes for the
IDT72V233, (2,049-m) writes for the IDT72V243, (4,097-m) writes for the
IDT72V253, (8,193-m) writes for the IDT72V263, (16,385-m) writes for the
IDT72V273, (32,769-m) writes for the IDT72V283 and (65,537-m) writes for
theIDT72V293.Ifbothx9Inputandx9OutputbusWidthsareselected,the
PAF
will go LOW after (1,025-m) writes for the IDT72V223, (2,049-m) writes for the
IDT72V233, (4,097-m) writes for the IDT72V243, (8,193-m) writes for the
IDT72V253, (16,385-m) writes for the IDT72V263, (32,769-m) writes for the
IDT72V273, (65,537-m) writes for the IDT72V283 and (131,073-m) writes for
the IDT72V293. The offset m is the full offset value. The default setting for this
value is stated in Table 2.
See Figure 18, Synchronous Programmable Almost-Full Flag Timing (IDT
Standard and FWFT Mode), for the relevant timing information.
If asynchronous
PAF configurationisselected,the PAF isassertedLOW
ontheLOW-to-HIGHtransitionoftheWriteClock(WCLK).
PAFisresettoHIGH
ontheLOW-to-HIGHtransitionoftheReadClock(RCLK).Ifsynchronous
PAF
configuration is selected, the
PAFisupdatedontherisingedgeofWCLK.See
Figure 20 for Asynchronous Programmable Almost-Full Flag Timing (IDT
Standard and FWFT Mode).
PROGRAMMABLE ALMOST-EMPTY FLAG (
PAE)
The Programmable Almost-Empty flag (
PAE)willgoLOWwhentheFIFO
reaches the almost-empty condition. In IDT Standard mode, PAE will go LOW
when there are n words or less in the FIFO. The offset “n” is the empty offset
value. The default setting for this value is stated in Table 2.
In FWFT mode, the
PAE will go LOW when there are n+1 words or less
in the FIFO. The default setting for this value is stated in Table 2.
See Figure 19, Synchronous Programmable Almost-Empty Flag Timing
(IDT Standard and FWFT Mode), for the relevant timing information.
If asynchronous
PAEconfigurationisselected,the PAEisassertedLOW
ontheLOW-to-HIGHtransitionoftheReadClock(RCLK).
PAEisresettoHIGH
ontheLOW-to-HIGHtransitionoftheWriteClock(WCLK).Ifsynchronous
PAE
configuration is selected, the
PAEisupdatedontherisingedgeofRCLK.See
Figure 21, Asynchronous Programmable Almost-Empty Flag Timing (IDT
Standard and FWFT Mode), for the relevant timing information.
HALF-FULL FLAG (
HF)
Thisoutputindicatesahalf-fullFIFO.TherisingWCLKedgethatfillstheFIFO
beyondhalf-fullsets
HFLOW.TheflagremainsLOWuntilthedifferencebetween
the write and read pointers becomes less than or equal to half of the total depth
of the device; the rising RCLK edge that accomplishes this condition sets
HF
HIGH.
InIDTStandardmode,ifnoreadsareperformedafterreset(
MRSorPRS),
HF will go LOW after (D/2 + 1) writes to the FIFO. If x18 Input or x18 Output
bus Width is selected, D = 512 for the IDT72V223, 1,024 for the IDT72V233,
2,048 for the IDT72V243, 4,096 for the IDT72V253, 8,192 for the IDT72V263,
16,384 for the IDT72V273, 32,768 for the IDT72V283 and 65,536 for the
IDT72V293. If both x9 Input and x9 Output bus Widths are selected, D = 1,024
for the IDT72V223, 2,048 for the IDT72V233, 4,096 for the IDT72V243, 8,192
for the IDT72V253, 16,384 for the IDT72V263, 32,768 for the IDT72V273,
65,536 for the IDT72V283 and 131,072 for the IDT72V293.
In FWFT mode, if no reads are performed after reset (
MRS or PRS), HF
will go LOW after (D-1/2 + 2) writes to the FIFO. If x18 Input or x18 Output bus
Width is selected, D = 513 for the IDT72V223, 1,025 for the IDT72V233, 2,049
fortheIDT72V243,4,097fortheIDT72V253,8,193fortheIDT72V263,16,385
for the IDT72V273, 32,769 for the IDT72V283 and 65,537 for the IDT72V293.
If both x9 Input and x9 Output bus Widths are selected, D = 1,025 for the
IDT72V223, 2,049 for the IDT72V233, 4,097 for the IDT72V243, 8,193 for the
IDT72V253, 16,385 for the IDT72V263, 32,769 for the IDT72V273, 65,537 for
the IDT72V283 and 131,073 for the IDT72V293.
See Figure 22, Half-Full Flag Timing (IDT Standard and FWFT Mode),
for the relevant timing information. Because
HFisupdatedbybothRCLKand
WCLK, it is considered asynchronous.
DATA OUTPUTS (Q0-Qn)
(Q0 - Q17) data outputs for 18-bit wide data or (Q0 - Q8) data outputs for 9-
bit wide data.