概觀
The 4Mb product family features high-speed, low-
power synchronous static RAMs designed to
provide a burstable, high-performance, 'no wait'
state, device for networking and communications
applications. They are organized as 128K words
by 36 bits and 256K words by 18 bits, fabricated
with ISSI's advanced CMOS technology.
Incorporating a 'no wait' state feature, wait cycles
are eliminated when the bus switches from read
to write, or write to read. This 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 are
controlled by a positive-edge-triggered single
clock input. Operations may be suspended and all
synchronous inputs ignored when Clock Enable,
/CKE is HIGH. In this state the internal device will
hold their previous values.
All Read, Write and Deselect cycles are initiated
by the ADV input. When the ADV is HIGH the
internal burst counter is incremented. New
external addresses can be loaded when ADV is
LOW.
Write cycles are internally self-timed and are
initiated by the rising edge of the clock inputs and
when /WE is LOW. Separate byte enables allow
individual bytes to be written.
A burst mode pin (MODE) defines the order of the
burst sequence. When tied HIGH, the interleaved
burst sequence is selected. When tied LOW, the
linear burst sequence is selected.