GS864236GB-250I Datasheet, PDF (1/37 Pages) GSI Technology – 4M x 18, 2M x 36, 1M x 72 72Mb S/DCD Sync Burst SRAMs

GS864218(B)/GS864236(B)/GS864272(C)
119- & 209-Pin BGA
Commercial Temp
Industrial Temp
4M x 18, 2M x 36, 1M x 72
72Mb S/DCD Sync Burst SRAMs
300 MHz–167 MHz
2.5 V or 3.3 V V_DD
2.5 V or 3.3 V I/O
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 +10%/–10% core power supply
• 3.3 V +10%/–10% 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
• Internal self-timed write cycle
• Automatic power-down for portable applications
• JEDEC-standard 119- and 209-bump BGA package
• RoHS-compliant 119- and 209-bump BGA packages available
Functional Description
Applications
The GS864218/36/72 is a 75,497,472-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
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 GS864218/36/72 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.
Pipeline
3-1-1-1
Flow Through
2-1-1-1
Parameter Synopsis
-300 -250 -200 -167 Unit
t_KQ(x18/x36)
t_KQ(x72)
tCycle
2.3
2.5
3.0
3.4
ns
3.0
3.0
3.0
3.4
ns
3.3
4.0
5.0
6.0
ns
Curr (x18)
Curr (x36)
Curr (x72)
400
340
290
260
mA
480
410
350
305
mA
590
520
435
380
mA
t_KQ
tCycle
5.5
6.5
7.5
8.0
ns
5.5
6.5
7.5
8.0
ns
Curr (x18)
Curr (x36)
Curr (x72)
285
245
220
210
mA
330
280
250
240
mA
425
370
315
300
mA
Rev: 1.04a 2/2009
1/36
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
© 2004, GSI Technology