GS840E18/32/36AT/B-190/180/166/150/100
TQFP, BGA
Commercial Temp
Industrial Temp
Features
• FT pin for user-configurable flow through or pipelined
operation
• Dual Cycle Deselect (DCD) operation
• 3.3 V +10%/–5% core power supply
• 2.5 V or 3.3 V 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
• Pb-Free 100-lead TQFP package available
256K x 18, 128K x 32, 128K x 36
4Mb Sync Burst SRAMs
190 MHz–100 MHz
3.3 V V
DD
3.3 V and 2.5 V I/O
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.
DCD Pipelined Reads
The GS840E18/32/36A 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.
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 GS840E18/32/36A operates on a 3.3 V power supply and
all inputs/outputs are 3.3 V- and 2.5 V-compatible. Separate
output power (V
DDQ
) pins are used to de-couple output noise
from the internal circuit.
Functional Description
Applications
The GS840E18/32/36A 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 CPUs, the device now finds application in
synchronous SRAM applications ranging from DSP main store
to networking chip set support. The GS84018/32/36A is
available in a JEDEC standard 100-lead TQFP or 119-Bump
BGA package.
Controls
Addresses, data I/Os, 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
Parameter Synopsis
–190
–180
–166
–150
–100
tCycle 5.3 ns 5.5 ns 6.0 ns 6.6 ns
10 ns
Pipeline
t
KQ
3.0 ns 3.0 ns 3.5 ns 3.8 ns 4.5 ns
3-1-1-1
I
DD
370 mA 335 mA 310 mA 280 mA 190 mA
Flow
t
KQ
7.5 ns
8 ns
8.5 ns
10 ns
12 ns
Through tCycle 8.5 ns
9 ns
10 ns
12 ns
15 ns
2-1-1-1
I
DD
245 mA 210 mA 190 mA 165 mA 135 mA
Rev: 1.12 10/2004
1/31
© 1999, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GSI [ GSI TECHNOLOGY ]
