IS61LF51218A
FEATURES
• Internal self-timed write cycle
• Individual Byte Write Control and Global Write
• Clock controlled, registered address, data and
control
• Burst sequence control using MODE input
• Three chip enable option for simple depth expansion
and address pipelining
• Common data inputs and data outputs
• Auto Power-down during deselect
• Single cycle deselect
• Snooze MODE for reduced-power standby
• JTAG Boundary Scan for PBGA package
• Power Supply
LF: Vdd 3.3V + 5%, Vddq 3.3V/2.5V + 5%
VF: Vdd 2.5V + 5%, Vddq 2.5V + 5%
• JEDEC 100-Pin TQFP, 119-pin PBGA, and 165-
pin PBGA packages
• Lead-free available
• Automotive temperature available
DESCRIPTION
The ISSI IS61LF/VF25636A, IS64LF25636A and IS61LF/
VF51218A are high-speed, low-power synchronous
static RAMs designed to provide burstable, high-performance
memory for communication and networking applications.
The IS61LF/VF25636A and IS64LF25636A are organized
as 262,144 words by 36 bits. The IS61LF/VF51218A is
organized as 524,288 words by 18 bits. Fabricated with
ISSI's advanced CMOS technology, the device integrates
a 2-bit burst counter, high-speed SRAM core, and highdrive
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.
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 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.
