
GS816272CC-333/300/250/200/150
256K x 72
18Mb S/DCD Sync Burst SRAMs
333 MHz
–
150 MHz
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
209-Bump BGA
Commercial Temp
Industrial Temp
Preliminary
Rev:  1.01  2/2005
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
1/31
 2004, GSI Technology
Features
 FT pin for user-configurable flow through or pipeline operation
 Single/Dual Cycle Deselect selectable
 IEEE 1149.1 JTAG-compatible Boundary Scan
 ZQ mode pin for user-selectable high/low output drive
 2.5 V or 3.3 V +10%/–10% core power supply
 LBO pin for Linear or Interleaved Burst mode
 Internal input resistors on mode pins allow floating mode pins
 Default to SCD x18/x36 Interleaved Pipeline mode
 Byte Write (BW) and/or Global Write (GW) operation
 Internal self-timed write cycle
 Automatic power-down for portable applications
 JEDEC-standard 209-bump BGA package
 Pb-Free 209-bump BGA package available
Functional Description
Applications
The GS816272CC is an 18,874,368-bit high performance 
synchronous SRAM with a 2-bit burst address counter. Although of a 
high performance CPUs, the device now finds application in 
synchronous SRAM applications, ranging from DSP main store to 
networking chip set support. 
Controls 
Addresses, data I/Os, chip enable (E1), 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 . Holding the FT mode pin low places the RAM in 
Flow Through mode, causing output data to bypass the Data Output 
Register. Holding FT high places the RAM in Pipeline mode, 
activating the rising-edge-triggered Data Output Register.
SCD and DCD Pipelined Reads
The GS816272CC is an SCD (Single Cycle Deselect) and DCD (Dual 
Cycle Deselect)  pipelined synchronous SRAM. DCD SRAMs 
pipeline disable commands to the same degree as read commands. 
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. 
DCD RAMs hold the deselect command for one full cycle and then 
begin turning off their outputs just after the second rising edge of 
clock. The user may configure this SRAM for either mode of 
operation using the SCD mode input. 
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. 
FLXDrive
The ZQ pin allows selection between high drive strength (ZQ low) for 
multi-drop bus applications and normal drive strength (ZQ floating or 
high) point-to-point applications. See the Output Driver 
Characteristics chart for details.
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 GS816272CC operates on a 2.5 V or 3.3 V power supply. All 
input are 3.3 V and 2.5 V compatible. Separate output power (V
DDQ
) 
pins are used to decouple output noise from the internal circuits and 
are 3.3 V and 2.5 V compatible.
Parameter Synopsis
-333
-300
-250
-200
-150
Unit
Pipeline
3-1-1-1
t
KQ
tCycle
Curr
t
KQ
tCycle
Curr 
2.8
3.0
2.8
3.3
3.0
4.0
3.0
5.0
3.8
6.7
ns
ns
545
4.5
4.5
380
495
5.0
5.0
345
425
5.5
5.5
315
345
6.5
6.5
275
270
7.5
7.5
250
mA
ns
ns
mA
Flow Through
2-1-1-1