GS816218(B/D)/GS816236(B/D)
119-, 165--Bump BGA
Commercial Temp
Industrial Temp
Features
1M x 18, 512K x 36
18Mb Sync Burst SRAMs
250 MHz–133 MHz
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
• 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 119-and 165-bump BGA packages
Data Output Register. Holding FT high places the RAM in
Pipeline mode, activating the rising-edge-triggered Data Output
Register.
Functional Description
Applications
The GS816218(B/D)/GS816236(B/D) is an 18,874,368-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.
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
SCD and DCD Pipelined Reads
The GS816218(B/D)/GS816236(B/D) 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.
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 GS816218(B/D)/GS816236(B/D) 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
-250
Pipeline
3-1-1-1
3.3 V
Flow Through
2-1-1-1
3.3 V
t
KQ
tCycle
Curr (x18)
Curr (x36)
t
KQ
tCycle
Curr (x18)
Curr (x36)
2.5
4.0
280
330
5.5
5.5
175
200
-225
2.7
4.4
255
300
6.0
6.0
165
190
-200
3.0
5.0
230
270
6.5
6.5
160
180
-166
3.4
6.0
200
230
7.0
7.0
150
170
-150
3.8
6.7
185
215
7.5
7.5
145
165
-133
4.0
7.5
165
190
8.5
8.5
135
150
Unit
ns
ns
mA
mA
ns
ns
mA
mA
Rev: 2.18 11/2005
1/38
© 1999, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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