GS840E18/32/36T/B-180/166/150/100
TQFP, BGA
Commercial Temp
Industrial Temp
Features
• FT pin for user configurable flow through or pipelined operation.
• Dual Cycle Deselect (DCD) 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
5.5ns
3.2ns
330mA
8ns
10ns
190mA
-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
256K x 18, 128K x 32, 128K x 36
4Mb Sync Burst SRAMs
Flow Through / Pipeline Reads
180Mhz - 100Mhz
3.3V VDD
3.3V & 2.5V I/O
be used. New addresses can be loaded on every cycle with no
degradation of chip performance.
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.
DCD Pipelined Reads
The GS840E18/32/36 is a DCD (Dual Cycle Deselect) pipelined
synchronous SRAM. SCD (Single Cycle Deselect) versions are also
available. DCD SRAMs pipeline disable commands to the same
degree as read commands. 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.
Pipeline
3-1-1-1
Flow Through
2-1-1-1
tCycle
t
KQ
I
DD
t
KQ
tCycle
I
DD
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.
Functional Description
Applications
The GS840E18/32/36 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 GS840E18/32/36
is available in a JEDEC standard 100-lead TQFP or 119 Bump BGA
package.
Core and Interface Voltages
The GS840E18/32/36 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.
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
Rev: 2.05 6/2000
1/31
© 1999, Giga Semiconductor, Inc.
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GSI [ GSI TECHNOLOGY ]
