22
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72V3640/50/60/70/80/90 3.3V HIGH DENSITY SUPERSYNC IITM 36-BIT FIFO
1,024 x 36, 2,048 x 36, 4,096 x 36, 8,192 x 36, 16,384 x 36 and 32,768 x 36
OCTOBER 22, 2008
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).
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, where D = 1,024 for the
IDT72V3640, 2,048 for the IDT72V3650, 4,096 for the IDT72V3660, 8,192
fortheIDT72V3670,16,384fortheIDT72V3680and32,768fortheIDT72V3690.
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, where D = 1,025 for the
IDT72V3640, 2,049 for the IDT72V3650, 4,097 for the IDT72V3660, 8,193 for
the IDT72V3670, 16,385 for the IDT72V3680 and 32,769 for the IDT72V3690.
See Figure 22, Half-Full Flag Timing (IDT Standard and FWFT Modes),
for the relevant timing information. Because
HFisupdatedbybothRCLKand
WCLK, it is considered asynchronous.
DATA OUTPUTS (Q0-Qn)
(Q0-Q35) are data outputs for 36-bit wide data, (Q0 - Q17) are data outputs
for 18-bit wide data or (Q0-Q8) are data outputs for 9-bit wide data.