AL4CS211/AL4CS221/AL4CS231/AL4CS241/AL4CS251
AL4CS211/AL4CS221/AL4CS231/AL4CS241/AL4CS251
December 14, 2001
4
1.0 Description
The AL4CS211/AL4CS221/AL4CS231/AL4CS241/AL4CS251 series memory products are high-
performance, low-power 9-bit read/write FIFO (First-In-First-Out) memory chips. They are
specially designed to buffer high speed streaming data for a wide range of communication
applications, such as optical disk controllers, Local Area Networks (LANs), SONET (Synchronous
Optical Network).
The input data is synchronous with a free-running clock (WCLK), and input-enable pins (/WEN1,
/WEN2). Data is written into the FIFO on every clock when enable pins are asserted. The output is
synchronous with the other free-running clock (RCLK) and enables (/REN1, /REN2).
An Output
Enable pin (/OE) is provided at the read port for tri-state control of the output port. The FIFOs can
output two fixed flags, Empty Flag( /EF) and Full Flag (/FF), and two programmable flags, Almost-
Empty (/PAE) and Almost-Full (/PAF). The offsets of the /PAE and /PAF flags are loaded when
Load pin (/LD) goes low.
2.0 Features
• 512 x9-bit cell array (AL4CS211)
• 1,024 x9-bit cell array (AL4CS221)
• 2,048 x9-bit cell array (AL4CS231)
• 4,096 x9-bit cell array (AL4CS241)
• 8,192 x9-bit cell array (AL4CS251)
• 100/133 MHz Operation
• 10/7.5 ns read/write cycle time
• Independent Read and Write operations
• Empty and Full flags support
• Programmable Almost-Empty and
Almost-Full flags
• Output enable (data skipping)
• 3.3V power supply with 5V tolerant
• Available in a 32-pin Thin Quad Flat
Pack (TQFP) and 32-pin plastic
leaded chip carrier (PLCC) packages
3.0 Applications
• Routers
• ATM switches
• Cable modems
• Wireless base stations
• SONET(Synchronous Optical Network) multiplexers
• Multimedia systems
• Time base correction (TBC)
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