Preliminary
GS88418/36B-200/180/166/150/133
119-Bump BGA
Commercial Temp
Industrial Temp
Features
• FT pin for user-configurable flow through or pipelined
operation
• Single/Dual Cycle Deselect Selectable
• ZQ mode pin for user-selectable high/low output drive strength
• 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 SCD x18/x36 Interleaved Pipeline 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
• 119-bump BGA package
512K x 18, 256K x 36
8Mb S/DCD Sync Burst SRAMs
Flow Through/Pipeline Reads
200 MHz–133 MHz
3.3 V V
DD
3.3 V and 2.5 V I/O
(LBO) input. The Burst function need not 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 bump (Bump 5R). 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 GS88436B is a 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 on Bump 4L.
Pipeline
3-1-1-1
Flow
Through
2-1-1-1
tCycle
t
KQ
I
DD
t
KQ
tCycle
I
DD
-200
5.0
3.0
450
7.5
10
270
-180
5. 5
3.2
410
8
10
270
-166
6.0
3.5
380
8.5
10
250
-150
6.7
3.8
350
9.0
10
240
-133
7.5
4.0
340
9.5
10
220
Unit
ns
ns
mA
ns
ns
mA
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.
Functional Description
Applications
The GS88418/36B is a 9,437,184-bit 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.
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.
Controls
Addresses, data I/Os, chip enables (E1, in x18 version, E1 and
E2 in x36 version), 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
Rev: 1.05 10/2001
1/25
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 GS884B 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 decouple output noise from the
internal circuit.
© 2000, Giga Semiconductor, Inc.
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GSI [ GSI TECHNOLOGY ]
