概觀
The 4Mb product family features high-speed, low-power
synchronous static RAMs designed to provide burstable,
high-performance memory for communication and
networking applications. The IS61(64)LF/VF12836EC are
organized as 131,072 words by 36bits. The
IS61(64)LF/VF12832EC are organized as 131,072 words by
32bits. The IS61(64)LF/VF25618EC are organized as 262,144
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 written.
The byte write operation is performed by using the 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 generated
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.
Interleave burst is achieved when this pin is tied HIGH or
left floating.