72261LA15TFI Integrated Device Technology (Idt), 72261LA15TFI Datasheet - Page 3

• Manufacturer Part Number: 72261LA15TFI
• Description: FIFO Mem Sync Dual Depth/Width Uni-Dir 16K x 9 64-Pin STQFP
• Manufacturer: Integrated Device Technology (Idt)

Specifications of 72261LA15TFI

• Package: 64STQFP
• Configuration: Dual
• Bus Directional: Uni-Directional
• Density: 144 Kb
• Organization: 16Kx9
• Data Bus Width: 9 Bit
• Timing Type: Synchronous
• Expansion Type: Depth|Width
• Typical Operating Supply Voltage: 5 V
• Operating Temperature: -40 to 85 °C

DESCRIPTION (CONTINUED)
to the data output lines after three transitions of the RCLK signal. A REN
does not have to be asserted for accessing the first word. However,
subsequent words written to the FIFO do require a LOW on REN for
access. The state of the FWFT/SI input during Master Reset determines
the timing mode in use.
FIFO can provide, the FWFT timing mode permits depth expansion by
chaining FIFOs in series (i.e. the data outputs of one FIFO are connected
to the corresponding data inputs of the next). No external logic is required.
FF/IR (Full Flag or Input Ready), HF (Half-full Flag), PAE (Programmable
Almost-Empty flag) and PAF (Programmable Almost-Full flag). The EF
and FF functions are selected in IDT Standard mode. The IR and OR
functions are selected in FWFT mode. HF, PAE and PAF are always
available for use, irrespective of timing mode.
in memory. (See Table I and Table II.) Programmable offsets determine
the flag switching threshold and can be loaded by two methods: parallel or
serial. Two default offset settings are also provided, so that PAE can be
set to switch at 127 or 1,023 locations from the empty boundary and the
PAF threshold can be set at 127 or 1,023 locations from the full boundary.
These choices are made with the LD pin during Master Reset.
WCLK, are used to load the offset registers via the Serial Input (SI). For
parallel programming, WEN together with LD on each rising edge of WCLK,
IDT72261LA/72271LA SuperSync FIFO™
16,384 x 9 and 32,768 x 9
In FWFT mode, the first word written to an empty FIFO is clocked directly
For applications requiring more data storage capacity than a single
PAE and PAF can be programmed independently to switch at any point
For serial programming, SEN together with LD on each rising edge of
FIRST WORD FALL THROUGH/SERIAL INPUT
These FIFOs have five flag pins, EF/OR (Empty Flag or Output Ready),
PROGRAMMABLE ALMOST-FULL (PAF)
FULL FLAG/INPUT READY (FF/IR)
Figure 1. Block Diagram of Single 16,384 x 9 and 32,768 x 9 Synchronous FIFO
WRITE CLOCK (WCLK)
WRITE ENABLE (WEN)
SERIAL ENABLE(SEN)
DATA IN (D
PARTIAL RESET (PRS)
LOAD (LD)
(FWFT/SI)
0
- D
n
)
72261LA
72271LA
3
IDT
are used to load the offset registers via Dn. REN together with LD on each rising
edge of RCLK can be used to read the offsets in parallel from Qn regardless
of whether serial or parallel offset loading has been selected.
pointers are set to the first location of the FIFO. The FWFT pin selects IDT
Standard mode or FWFT mode. The LD pin selects either a partial flag default
setting of 127 with parallel programming or a partial flag default setting of 1,023
with serial programming. The flags are updated according to the timing mode
and default offsets selected.
location of the memory. However, the timing mode, partial flag program-
ming method, and default or programmed offset settings existing before
Partial Reset remain unchanged. The flags are updated according to the
timing mode and offsets in effect. PRS is useful for resetting a device in
mid-operation, when reprogramming partial flags would be undesirable.
than once. A LOW on the RT input during a rising RCLK edge initiates a
retransmit operation by setting the read pointer to the first location of the
memory array.
will automatically power down. Once in the power down state, the standby
supply current consumption is minimized. Initiating any operation (by
activating control inputs) will immediately take the device out of the power
down state.
micron CMOS technology.
MASTER RESET (MRS)
During Master Reset (MRS) the following events occur: The read and write
The Partial Reset (PRS) also sets the read and write pointers to the first
The Retransmit function allows data to be reread from the FIFO more
If, at any time, the FIFO is not actively performing an operation, the chip
The IDT72261LA/72271LA are fabricated using IDT’s high speed sub-
READ CLOCK (RCLK)
READ ENABLE (REN)
RETRANSMIT (RT)
EMPTY FLAG/OUTPUT READY (EF/OR)
PROGRAMMABLE ALMOST-EMPTY (PAE)
HALF FULL FLAG (HF)
DATA OUT (Q
OUTPUT ENABLE (OE)
0
- Q
COMMERCIAL AND INDUSTRIAL
n
)
TEMPERATURE RANGES
JANUARY 7, 2009
4671 drw 03