GS8644Z18/36E-xxxV
165-Bump BGA
Commercial Temp
Industrial Temp
Features
• NBT (No Bus Turn Around) functionality allows zero wait
Read-Write-Read bus utilization; fully pin-compatible with
both pipelined and flow through NtRAM™, NoBL™ and
ZBT™ SRAMs
• 1.8 V or 2.5 V core power supply and I/O supply
• User-configurable Pipeline and Flow Through mode
• ZQ mode pin for user-selectable high/low output drive
• IEEE 1149.1 JTAG-compatible Boundary Scan
• LBO pin for Linear or Interleave Burst mode
• Pin-compatible with 2Mb, 4Mb, 9Mb, 18Mb, and 36Mb
devices
• Byte write operation (9-bit Bytes)
• 3 chip enable signals for easy depth expansion
• ZZ Pin for automatic power-down
• JEDEC-standard 165-bump BGA package
• RoHS-compliant 165-bump BGA package available
72Mb Pipelined and Flow Through
Synchronous NBT SRAM
250 MHz–133MHz
1.8 V or 2.5 V V
DD
1.8 V or 2.5 V I/O
Because it is a synchronous device, address, data inputs, and
read/write control inputs are captured on the rising edge of the
input clock. Burst order control (LBO) must be tied to a power
rail for proper operation. Asynchronous inputs include the
Sleep mode enable (ZZ) and Output Enable. Output Enable can
be used to override the synchronous control of the output
drivers and turn the RAM's output drivers off at any time.
Write cycles are internally self-timed and initiated by the rising
edge of the clock input. This feature eliminates complex off-
chip write pulse generation required by asynchronous SRAMs
and simplifies input signal timing.
The GS8644Z18/36E-xxxV may be configured by the user to
operate in Pipeline or Flow Through mode. Operating as a
pipelined synchronous device, in addition to the rising-edge-
triggered registers that capture input signals, the device
incorporates a rising edge triggered output register. For read
cycles, pipelined SRAM output data is temporarily stored by
the edge-triggered output register during the access cycle and
then released to the output drivers at the next rising edge of
clock.
The GS8644Z18/36E-xxxV is implemented with GSI's high
performance CMOS technology and is available in a JEDEC-
standard 165-bump BGA package.
Functional Description
The GS8644Z18/36E-xxxV is a 72Mbit Synchronous Static
SRAM. GSI's NBT SRAMs, like ZBT, NtRAM, NoBL or
other pipelined read/double late write or flow through read/
single late write SRAMs, allow utilization of all available bus
bandwidth by eliminating the need to insert deselect cycles
when the device is switched from read to write cycles.
Parameter Synopsis
-250 -225 -200 -166 -150 -133 Unit
Pipeline
3-1-1-1
t
KQ
tCycle
Curr (x18)
Curr (x36)
t
KQ
tCycle
Curr (x18)
Curr (x36)
3.0
4.0
385
450
6.5
6.5
265
290
3.0
4.4
360
415
6.5
6.5
265
290
3.0
5.0
335
385
6.5
6.5
265
290
3.0
6.0
305
345
8.0
8.0
255
280
3.3
6.7
295
325
8.5
8.5
240
265
3.5
7.5
265
295
8.5
8.5
225
245
ns
ns
mA
mA
ns
ns
mA
mA
Flow
Through
2-1-1-1
Rev: 1.06 3/2009
1/30
© 2003, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8644Z18/36E-xxxV
165 Bump BGA—x18 Common I/O—Top View (Package E)
1
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
NC
NC
NC
NC
NC
NC
NC
FT
DQB
DQB
DQB
DQB
DQPB
NC
LBO
2
A
A
NC
DQB
DQB
DQB
DQB
MCH
NC
NC
NC
NC
NC
A
A
3
E1
E2
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
NC
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
A
A
4
BB
NC
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
A
A
5
NC
BA
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
NC
TDI
TMS
6
E3
CK
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
NC
A1
A0
7
CKE
W
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
NC
TDO
TCK
8
ADV
G
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
A
A
9
A
A
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
NC
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
A
A
10
A
A
NC
NC
NC
NC
NC
ZQ
DQA
DQA
DQA
DQA
NC
A
A
11
A
NC
DQPA
DQA
DQA
DQA
DQA
ZZ
NC
NC
NC
NC
NC
NC
A
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
11 x 15 Bump BGA—15 mm x 17 mm Body—1.0 mm Bump Pitch
Rev: 1.06 3/2009
2/30
© 2003, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8644Z18/36E-xxxV
165 Bump BGA—x36 Common I/O—Top View (Package E)
1
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
NC
NC
DQPC
DQC
DQC
DQC
DQC
FT
DQD
DQD
DQD
DQD
DQPD
NC
LBO
2
A
A
NC
DQC
DQC
DQC
DQC
MCH
DQD
DQD
DQD
DQD
NC
A
A
3
E1
E2
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
NC
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
A
A
4
BC
BD
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
A
A
5
BB
BA
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
NC
TDI
TMS
6
E3
CK
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
NC
A1
A0
7
CKE
W
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
NC
TDO
TCK
8
ADV
G
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
A
A
9
A
A
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
NC
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
A
A
10
A
A
NC
DQB
DQB
DQB
DQB
ZQ
DQA
DQA
DQA
DQA
NC
A
A
11
NC
NC
DQPB
DQB
DQB
DQB
DQB
ZZ
DQA
DQA
DQA
DQA
DQPA
NC
A
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
11 x 15 Bump BGA—15 mm x 17 mm Body—1.0 mm Bump Pitch
Rev: 1.06 3/2009
3/30
© 2003, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8644Z18/36E-xxxV
GS8644Z18/36E-xxxV 165-Bump BGA Pin Description
Symbol
A
0
, A
1
A
DQ
A
DQ
B
DQ
C
DQ
D
B
A
, B
B
, B
C
, B
D
NC
CK
CKE
W
E
1
E
3
E
2
FT
G
ADV
ZQ
ZZ
LBO
TMS
TDI
TDO
TCK
MCH
V
DD
V
SS
V
DDQ
Type
I
I
I/O
I
—
I
I
I
I
I
I
I
I
I
I
I
I
I
I
O
I
—
I
I
I
Description
Address field LSBs and Address Counter Preset Inputs
Address Inputs
Data Input and Output pins
Byte Write Enable for DQ
A
, DQ
B
, DQ
C
, DQ
D
I/Os; active low
No Connect
Clock Input Signal; active high
Clock Enable; active low
Write Enable; active low
Chip Enable; active low
Chip Enable; active low
Chip Enable; active high
Flow Through / Pipeline Mode Control
Output Enable; active low
Burst address counter advance enable; active high
FLXDrive Output Impedance Control
Low = Low Impedance [High Drive], High = High Impedance [Low Drive])
Sleep mode control; active high
Linear Burst Order mode; active low
Scan Test Mode Select
Scan Test Data In
Scan Test Data Out
Scan Test Clock
Must Connect High
Core power supply
I/O and Core Ground
Output driver power supply
Rev: 1.06 3/2009
4/30
© 2003, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8644Z18/36E-xxxV
Functional Details
Clocking
Deassertion of the Clock Enable (CKE) input blocks the Clock input from reaching the RAM's internal circuits. It may be used to
suspend RAM operations. Failure to observe Clock Enable set-up or hold requirements will result in erratic operation.
Pipeline Mode Read and Write Operations
All inputs (with the exception of Output Enable, Linear Burst Order and Sleep) are synchronized to rising clock edges. Single cycle
read and write operations must be initiated with the Advance/Load pin (ADV) held low, in order to load the new address. Device
activation is accomplished by asserting all three of the Chip Enable inputs (E
1
, E
2,
and E
3
). Deassertion of any one of the Enable
inputs will deactivate the device.
Function
Read
Write Byte “a”
Write Byte “b”
Write Byte “c”
Write Byte “d”
Write all Bytes
Write Abort/NOP
W
H
L
L
L
L
L
L
B
A
X
L
H
H
H
L
H
B
B
X
H
L
H
H
L
H
B
C
X
H
H
L
H
L
H
B
D
X
H
H
H
L
L
H
Read operation is initiated when the following conditions are satisfied at the rising edge of clock: CKE is asserted low, all three
chip enables (E
1
, E
2,
and E
3
) are active, the write enable input signals W is deasserted high, and ADV is asserted low. The address
presented to the address inputs is latched into the address register and presented to the memory core and control logic. The control
logic determines that a read access is in progress and allows the requested data to propagate to the input of the output register. At
the next rising edge of clock the read data is allowed to propagate through the output register and onto the output pins.
Write operation occurs when the RAM is selected, CKE is active, and the Write input is sampled low at the rising edge of clock.
The Byte Write Enable inputs (B
A
, B
B
, B
C,
and B
D
) determine which bytes will be written. All or none may be activated. A write
cycle with no Byte Write inputs active is a no-op cycle. The pipelined NBT SRAM provides double late write functionality,
matching the write command versus data pipeline length (2 cycles) to the read command versus data pipeline length (2 cycles). At
the first rising edge of clock, Enable, Write, Byte Write(s), and Address are registered. The Data In associated with that address is
required at the third rising edge of clock.
Flow Through Mode Read and Write Operations
Operation of the RAM in Flow Through mode is very similar to operations in Pipeline mode. Activation of a Read Cycle and the
use of the Burst Address Counter is identical. In Flow Through mode the device may begin driving out new data immediately after
new address are clocked into the RAM, rather than holding new data until the following (second) clock edge. Therefore, in Flow
Through mode the read pipeline is one cycle shorter than in Pipeline mode.
Write operations are initiated in the same way, but differ in that the write pipeline is one cycle shorter as well, preserving the ability
to turn the bus from reads to writes without inserting any dead cycles. While the pipelined NBT RAMs implement a double late
write protocol in Flow Through mode a single late write protocol mode is observed. Therefore, in Flow Through mode, address
and control are registered on the first rising edge of clock and data in is required at the data input pins at the second rising edge of
clock.
Rev: 1.06 3/2009
5/30
© 2003, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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