GS8182T19/37BD-435/400/375/333/300
165-Bump BGA
Commercial Temp
Industrial Temp
Features
• 2.0 Clock Latency
• Simultaneous Read and Write SigmaDDR-II™ Interface
• Common I/O bus
• JEDEC-standard pinout and package
• Double Data Rate interface
• Byte Write (x36 and x18) function
• Burst of 2 Read and Write
• 1.8 V +100/–100 mV core power supply
• 1.5 V or 1.8 V HSTL Interface
• Pipelined read operation with self-timed Late Write
• Fully coherent read and write pipelines
• ZQ pin for programmable output drive strength
• IEEE 1149.1 JTAG-compliant Boundary Scan
• 165-bump, 13 mm x 15 mm, 1 mm bump pitch BGA package
• RoHS-compliant 165-bump BGA package available
18Mb SigmaDDR-II+
TM
Burst of 2 SRAM
435 MHz–300 MHz
1.8 V V
DD
1.8 V and 1.5 V I/O
just one element in a family of low power, low voltage HSTL
I/O SRAMs designed to operate at the speeds needed to
implement economical high performance networking systems.
Clocking and Addressing Schemes
The GS8182T19/37BD SigmaDDR-II+ SRAMs are
synchronous devices. They employ two input register clock
inputs, K and K. K and K are independent single-ended clock
inputs, not differential inputs to a single differential clock input
buffer.
Each internal read and write operation in a SigmaDDR-II+ B2
RAM is two times wider than the device I/O bus. An input data
bus de-multiplexer is used to accumulate incoming data before
it is simultaneously written to the memory array. An output
data multiplexer is used to capture the data produced from a
single memory array read and then route it to the appropriate
output drivers as needed. Therefore the address field of a
SigmaDDR-II+ B2 RAM is always one address pin less than
the advertised index depth (e.g., the 2M x 8 has a 1M
addressable index).
SigmaDDR-II™ Family Overview
The GS8182T19/37BD are built in compliance with the
SigmaDDR-II+ SRAM pinout standard for Common I/O
synchronous SRAMs. They are 18,874,368-bit (18Mb)
SRAMs. The GS8182T19/37BD SigmaDDR-II SRAMs are
Parameter Synopsis
-435
tKHKH
tKHQV
2.3 ns
0.45 ns
-400
2.5 ns
0.45 ns
-375
2.67 ns
0.45 ns
-333
3.0 ns
0.45 ns
-300
3.3 ns
0.45 ns
Rev: 1.03a 11/2011
1/27
© 2008, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8182T19/37BD-435/400/375/333/300
512K x 36 SigmaDDR-II+ SRAM—Top View
1
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
CQ
NC
NC
NC
NC
NC
NC
Doff
NC
NC
NC
NC
NC
NC
TDO
2
NC/SA
(144Mb)
DQ27
NC
DQ29
NC
DQ30
DQ31
V
REF
NC
NC
DQ33
NC
DQ35
NC
TCK
3
NC/SA
(36Mb)
DQ18
DQ28
DQ19
DQ20
DQ21
DQ22
V
DDQ
DQ32
DQ23
DQ24
DQ34
DQ25
DQ26
SA
4
R/W
SA
V
SS
V
SS
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
SS
V
SS
SA
SA
5
BW2
BW3
SA
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
SA
SA
SA
6
K
K
NC
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
SA
QVLD
NC
7
BW1
BW0
SA
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
SA
SA
SA
8
LD
SA
V
SS
V
SS
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
SS
V
SS
SA
SA
9
SA
NC/SA
(288Mb)
NC
NC
NC
NC
NC
V
DDQ
NC
NC
NC
NC
NC
NC
SA
10
NC/SA
(72Mb)
NC
DQ17
NC
DQ15
NC
NC
V
REF
DQ13
DQ12
NC
DQ11
NC
DQ9
TMS
11
CQ
DQ8
DQ7
DQ16
DQ6
DQ5
DQ14
ZQ
DQ4
DQ3
DQ2
DQ1
DQ10
DQ0
TDI
11 x 15 Bump BGA—13 x 15 mm
2
Body—1 mm Bump Pitch
Notes:
1. BW0 controls writes to DQ0:DQ8; BW1 controls writes to DQ9:DQ17; BW2 controls writes to DQ18:DQ26; BW3 controls writes to
DQ27:DQ35
2. NC = Not connected
Rev: 1.03a 11/2011
2/27
© 2008, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8182T19/37BD-435/400/375/333/300
1M x 18 SigmaDDR-II+ SRAM—Top View
1
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
CQ
NC
NC
NC
NC
NC
NC
Doff
NC
NC
NC
NC
NC
NC
TDO
2
NC/SA
(72Mb)
DQ9
NC
NC
NC
DQ12
NC
V
REF
NC
NC
DQ15
NC
NC
NC
TCK
3
SA
NC
NC
DQ10
DQ11
NC
DQ13
V
DDQ
NC
DQ14
NC
NC
DQ16
DQ17
SA
4
R/W
SA
V
SS
V
SS
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
SS
V
SS
SA
SA
5
BW1
NC/SA
(288Mb)
SA
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
SA
SA
SA
6
K
K
NC
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
SA
QVLD
NC
7
NC/SA
(144Mb)
BW0
SA
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
SA
SA
SA
8
LD
SA
V
SS
V
SS
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
DDQ
V
SS
V
SS
SA
SA
9
SA
NC
NC
NC
NC
NC
NC
V
DDQ
NC
NC
NC
NC
NC
NC
SA
10
NC/SA
(36 Mb)
NC
DQ7
NC
NC
NC
NC
V
REF
DQ4
NC
NC
DQ1
NC
NC
TMS
11
CQ
DQ8
NC
NC
DQ6
DQ5
NC
ZQ
NC
DQ3
DQ2
NC
NC
DQ0
TDI
11 x 15 Bump BGA—13 x 15 mm
2
Body—1 mm Bump Pitch
Notes:
1. BW0 controls writes to DQ0:DQ8; BW1 controls writes to DQ9:DQ17
2. NC = Not connected
Rev: 1.03a 11/2011
3/27
© 2008, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8182T19/37BD-435/400/375/333/300
Pin Description Table
Symbol
SA
R/W
BW0–BW3
LD
K
K
TMS
TDI
TCK
TDO
V
REF
ZQ
MCL
DQ
Description
Synchronous Address Inputs
Synchronous Read/ Write
Synchronous Byte Writes
Synchronous Load Pin
Input Clock
Input Clock
Test Mode Select
Test Data Input
Test Clock Input
Test Data Output
HSTL Input Reference Voltage
Output Impedance Matching Input
Must Connect Low
Data I/O
Disable DLL when low
Output Echo Clock
Output Echo Clock
Power Supply
Isolated Output Buffer Supply
Power Supply: Ground
Q Valid Output
No Connect
Type
Input
Input
Input
Input
Input
Input
Input
Input
Input
Output
Input
Input
—
Input/Output
Input
Output
Output
Supply
Supply
Supply
Output
—
Comments
—
Read Active when High
Active Low
Active Low
Active High
Active Low
—
—
—
—
—
—
—
Three State
Active Low
—
—
1.8 V Nominal
1.5 V or 1.8 V Nominal
—
—
—
Doff
CQ
CQ
V
DD
V
DDQ
V
SS
QVLD
NC
Notes:
1. NC = Not Connected to die or any other pin
2. When ZQ pin is directly connected to V
DDQ
, output impedance is set to minimum value and it cannot be connected to ground or left
unconnected.
3. K, K cannot be set to V
REF
voltage
Rev: 1.03a 11/2011
4/27
© 2008, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8182T19/37BD-435/400/375/333/300
Background
Common I/O SRAMs, from a system architecture point of view, are attractive in read dominated or block transfer applications.
Therefore, the SigmaDDR-II+ SRAM interface and truth table are optimized for burst reads and writes. Common I/O SRAMs are
unpopular in applications where alternating reads and writes are needed because bus turnaround delays can cut high speed
Common I/O SRAM data bandwidth in half.
Burst Operations
Read and write operations are "burst" operations. In every case where a read or write command is accepted by the SRAM, it will
respond by issuing or accepting two beats of data, executing a data transfer on subsequent rising edges of K and K, as illustrated in
the timing diagrams. This means that it is possible to load new addresses every K clock cycle. Addresses can be loaded less often,
if intervening deselect cycles are inserted.
Deselect Cycles
Chip Deselect commands are pipelined to the same degree as read commands. This means that if a deselect command is applied to
the SRAM on the next cycle after a read command captured by the SRAM, the device will complete the two beat read data transfer
and then execute the deselect command, returning the output drivers to high-Z. A high on the LD pin prevents the RAM from
loading read or write command inputs and puts the RAM into deselect mode as soon as it completes all outstanding burst transfer
operations.
SigmaDDR-II+ B2 SRAM Read Cycles
The SRAM executes pipelined reads. The status of the Address, LD and R/W pins are evaluated on the rising edge of K. The read
command (LD low and R/W high) is clocked into the SRAM by a rising edge of K.
SigmaDDR-II+ B2 SRAM Write Cycles
The status of the Address, LD and R/W pins are evaluated on the rising edge of K. The SRAM executes "late write" data transfers.
Data in is due at the device inputs on the rising edge of K following the rising edge of K clock used to clock in the write command
(LD and R/W low) and the write address. To complete the remaining beat of the burst of two write transfer, the SRAM captures
data in on the next rising edge of K, for a total of two transfers per address load.
Rev: 1.03a 11/2011
5/27
© 2008, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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