Overview
The 72Mb product family features high-speed, low-power
synchronous static RAMs designed to provide burstable,
high-performance memory for communication and network-
ing applications. The IS61LF/VF204836B is organized as
2,096,952 words by 36 bits. The IS61LF/VF409618B is
organized as 4,193,904 words by 18 bits. Fabricated with
ISSI's advanced CMOS technology, the device integrates
a 2-bit burst counter, high-speed SRAM core, and high-
drive capability outputs into a single monolithic circuit. All
synchronous inputs pass through registers controlled by
a positive-edge-triggered single clock input.
Write cycles are internally self-timed and are initiated by the
rising edge of the clock input. Write cycles can be one to
four bytes wide as controlled by the write control inputs.
Separate byte enables allow individual bytes to be writ-
ten. Byte write operation is performed by using byte write
enable (BWE) input combined with one or more individual
byte write signals (BWx). In addition, Global Write (GW)
is available for writing all bytes at one time, regardless of
the byte write controls.
Bursts can be initiated with either ADSP (Address Status
Processor) or ADSC (Address Status Cache Controller)
input pins. Subsequent burst addresses can be gener-
ated internally and controlled by the ADV (burst address
advance) input pin.
The mode pin is used to select the burst sequence order,
Linear burst is achieved when this pin is tied LOW. Inter-
leave burst is achieved when this pin is tied HIGH or left
floating.