Choice of Memory Organizations
– SN74V263 – 8192 × 18/16384 × 9
– SN74V273 – 16384 × 18/32768 × 9
– SN74V283 – 32768 × 18/65536 × 9
– SN74V293 – 65536 × 18/131072 × 9
166-MHz Operation
6-ns Read/Write Cycle Time
User-Selectable Input and Output Port Bus
Sizing
– ×9 in to ×9 out
– ×9 in to ×18 out
– ×18 in to ×9 out
– ×18 in to ×18 out
Big-Endian/Little-Endian User-Selectable
Byte Representation
5-V-Tolerant Inputs
Fixed, Low First-Word Latency
Zero-Latency Retransmit
Master Reset Clears Entire FIFO
Partial Reset Clears Data, but Retains
Programmable Settings
Empty, Full, and Half-Full Flags Signal FIFO
Status
Programmable Almost-Empty and
Almost-Full Flags; Each Flag Can Default to
One of Eight Preselected Offsets
Selectable Synchronous/Asynchronous
Timing Modes for Almost-Empty and
Almost-Full Flags
Program Programmable Flags by Either
Serial or Parallel Means
Select Standard Timing (Using EF and FF
Flags) or First-Word Fall-Through (FWFT)
Timing (Using OR and IR Flags)
Output Enable Puts Data Outputs in
High-Impedance State
Easily Expandable in Depth and Width
Independent Read and Write Clocks Permit
Reading and Writing Simultaneously
High-Performance Submicron CMOS
Technology
Glueless Interface With ’C6x DSPs
Available in 80-Pin Thin Quad Flat Pack
(TQFP) and 100-Pin Ball Grid Array (BGA)
Packages

description
The SN74V263, SN74V273, SN74V283, and SN74V293 are exceptionally deep, high-speed, CMOS first-in
first-out (FIFO) memories with clocked read and write controls and a flexible bus-matching ×9/×18 data flow.
There is flexible ×9/×18 bus matching on both read and write ports.
The period required by the retransmit operation is fixed and short.
The first-word data-latency period, from the time the first word is written to an empty FIFO to the time it can be
read, is fixed and short.
These FIFOs are particularly appropriate for network, video, telecommunications, data communications, and
other applications that need to buffer large amounts of data and match buses of unequal sizes.
Each FIFO has a data input port (Dn) and a data output port (Qn), both of which can assume either an 18-bit
or 9-bit width, as determined by the state of external control pins’ input width (IW) and output width (OW) during
the master-reset cycle.
The input port is controlled by write-clock (WCLK) and write-enable (WEN) inputs. Data is written into the FIFO
on every rising edge of WCLK when WEN is asserted. The output port is controlled by read-clock (RCLK) and
read-enable (REN) inputs. Data is read from the FIFO on every rising edge of RCLK when REN is asserted.
An output-enable (OE) input is provided for 3-state control of the outputs.