®
IS61VPS25636A IS61LPS25636A
IS61VPS51218A IS61LPS51218A
ISSI
256K x 36, 512K x 18
MAY 2005
9 Mb SYNCHRONOUS PIPELINED,
SINGLE CYCLE DESELECT STATIC RAM
DESCRIPTION
FEATURES
The ISSI IS61LPS/VPS25636A and IS61LPS/
VPS51218Aarehigh-speed,low-powersynchronousstatic
RAMsdesignedtoprovideburstable,high-performancememory
for communication and networking applications. The
IS61LPS/VPS25636A is organized as 262,144 words by
36 bits and the IS61LPS/VPS51218A is organized as
524,288 words by 18 bits. Fabricated with ISSI's ad-
vanced 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.
• 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
Write cycles are internally self-timed and are initiated by
therisingedgeoftheclockinput. Writecyclescanbeone
tofourbyteswideascontrolledbythewritecontrolinputs.
• Snooze MODE for reduced-power standby
• JTAG Boundary Scan for PBGA package
• Power Supply
Separatebyteenablesallowindividualbytestobewritten.
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.
LPS: VDD 3.3V + 5%, VDDQ 3.3V/2.5V + 5%
VPS: VDD 2.5V + 5%, VDDQ 2.5V + 5%
Bursts can be initiated with either ADSP (Address Status
Processor) or ADSC (Address Status Cache Controller)
inputpins.Subsequentburstaddressescanbegenerated
internally and controlled by the ADV (burst address
advance) input pin.
• JEDEC 100-Pin TQFP, 119-ball PBGA, and
165-ball PBGA packages
• Lead-free available
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.
FAST ACCESS TIME
Symbol
tKQ
Parameter
250
2.6
4
200
3.1
5
Units
ns
Clock Access Time
Cycle Time
tKC
ns
Frequency
250
200
MHz
Copyright © 2005 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability
arisingoutoftheapplicationoruseofanyinformation, productsorservicesdescribedherein. Customersareadvisedtoobtainthelatestversionofthisdevicespecificationbeforerelyingonany
publishedinformationandbeforeplacingordersforproducts.
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. A
1
04/29/05