
Rev:  2.05  6/2000
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
1/31
 1999, Giga Semiconductor, Inc.
GS84018/32/36T/B-180/166/150/100
 256K x 18, 128K x 32, 128K x 36
4Mb Sync Burst SRAMs
180Mhz - 100Mhz
3.3V VDD
3.3V & 2.5V I/O
TQFP, BGA
Commercial Temp
Industrial Temp
Features
 FT pin for user configurable flow through or pipelined operation.
 Single Cycle Deselect (SCD) Operation.
 3.3V +10%/-5% Core power supply
 2.5V or 3.3V I/O supply.
 LBO pin for linear or interleaved burst mode.
 Internal input resistors on mode pins allow floating mode pins.
 Default to Interleaved Pipelined Mode.
 Byte write (BW) and/or global write (GW) operation.
 Common data inputs and data outputs.
 Clock Control, registered, address, data, and control.
 Internal Self-Timed Write cycle.
 Automatic power-down for portable applications.
 JEDEC standard 100-lead TQFP or 119 Bump BGA  package.
-180
tCycle
t
KQ
I
DD
330mA
t
KQ
tCycle
I
DD
190mA
Functional Description
Applications
The GS84018/32/36 is a 4,718,592 bit  (4,194,304 bit for x32 version) 
high performance synchronous SRAM with a 2 bit burst address 
counter. Although of a type originally developed for Level 2 Cache 
applications supporting high performance CPU’s, the device now 
finds application in synchronous SRAM applications ranging from 
DSP main store to networking chip set support. The GS84018/32/36 
is available in a JEDEC standard 100-lead TQFP or 119 Bump BGA  
package.
Controls 
Addresses, data I/O’s, chip enables (E
1
, E
2
, E
3
), address burst control 
inputs (ADSP, ADSC, ADV) and write control inputs (Bx, BW, GW) are 
synchronous and are controlled by a positive edge triggered clock 
input (CK). Output enable (G) and power down control (ZZ) are 
asynchronous inputs. Burst cycles can be initiated with either ADSP 
or ADSC inputs. In Burst mode, subsequent burst addresses are 
generated internally and are controlled by ADV. The burst address 
counter may be configured to count in either linear or interleave order 
with the Linear Burst Order (LBO) input. The Burst function need not 
be used. New addresses can be loaded on every cycle with no 
degradation of chip performance.
Flow Through / Pipeline Reads
The function of the Data Output register can be controlled by the user 
via the FT mode pin/bump (pin 14 in the TQFP and  bump 5R in the 
BGA, ) . Holding the FT mode pin/bump low places the RAM in Flow 
through mode, causing output data to bypass the Data Output 
Register. Holding FT high places the RAM in Pipelined Mode, 
activating the rising edge triggered Data Output Register.
SCD Pipelined Reads
The GS84018/32/36 is an SCD (Single Cycle Deselect) pipelined 
synchronous SRAM. DCD (Dual Cycle Deselect) versions are also 
available.SCD SRAMs pipeline deselect commands one stage less 
than read commands. SCD RAMs begin turning off their outputs 
immediately after the deselect command has been captured in the 
input registers. 
Byte Write and Global Write
Byte write operation is performed by using byte write enable (BW) 
input combined with one or more individual byte write signals (Bx). In 
addition, Global Write (GW) is available for writing all bytes at one 
time, regardless of the Byte Write control inputs. 
Sleep Mode
Low power (Sleep mode) is attained through the assertion (High) of 
the ZZ signal, or by stopping the clock (CK). Memory data is retained 
during Sleep mode. 
Core and Interface Voltages
The GS84018/32/36 operates on a 3.3V power supply and all inputs/
outputs are 3.3V and 2.5V compatible. Separate output power (V
DDQ
) 
pins are used to de-couple output noise from the internal circuit.
-166
6.0ns
3.5ns
310mA
8.5ns
10ns
190mA
-150
6.6ns
3.8ns
275mA
10ns
10ns
190mA
-100
10ns
4.5ns
190mA
12ns
15ns
140mA
Pipeline
3-1-1-1
5.5ns
3.2ns
Flow Through
2-1-1-1
8ns
10ns
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