Cypress CY7C1556V18-300BZC 72-mbit qdrâ ¢-ii sram 4-word burst architecture (2.0 cycle read latency) Datasheet

CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
72-Mbit QDR™-II+ SRAM 4-Word Burst
Architecture (2.0 Cycle Read Latency)
Features
Configurations
■
Separate independent read and write data ports
❐ Supports concurrent transactions
With Read Cycle Latency of 2.0 cycles:
■
300 MHz to 375 MHz clock for high bandwidth
CY7C1556V18 – 8M x 9
■
4-Word burst for reducing address bus frequency
CY7C1543V18 – 4M x 18
■
Double Data Rate (DDR) interfaces on both Read and Write
Ports (data transferred at 750 MHz) at 375 MHz
CY7C1545V18 – 2M x 36
■
Available in 2.0 clock cycle latency
■
Two input clocks (K and K) for precise DDR timing
❐ SRAM uses rising edges only
■
Echo clocks (CQ and CQ) simplify data capture in high speed
systems
■
Data valid pin (QVLD) to indicate valid data on the output
■
Single multiplexed address input bus latches address inputs
for both Read and Write Ports
■
Separate Port Selects for depth expansion
■
Synchronous internally self-timed writes
■
Available in x8, x9, x18, and x36 configurations
■
Full data coherency providing most current data
■
Core VDD = 1.8V ± 0.1V; IO VDDQ = 1.4V to VDD[1]
■
HSTL inputs and variable drive HSTL output buffers
■
Available in 165-ball FBGA package (15 x 17 x 1.4 mm)
■
Offered in both Pb-free and non Pb-free packages
■
JTAG 1149.1 compatible test access port
■
Delay Lock Loop (DLL) for accurate data placement
CY7C1541V18 – 8M x 8
Functional Description
The CY7C1541V18, CY7C1556V18, CY7C1543V18, and
CY7C1545V18 are 1.8V Synchronous Pipelined SRAMs,
equipped with QDR-II+ architecture. Similar to QDR-II architecture, QDR-II+ SRAMs consists of two separate ports to
access the memory array. The Read Port has dedicated Data
Outputs to support read operations and the Write Port has
dedicated Data Inputs to support write operations. QDR-II+
architecture has separate data inputs and data outputs to
completely eliminate the need to “turn-around” the data bus
required with common IO devices. Access to each port is accomplished through a common address bus. Addresses for read and
write addresses are latched on alternate rising edges of the input
(K) clock. Accesses to the QDR-II+ Read and Write Ports are
completely independent of one another. In order to maximize
data throughput, both Read and Write Ports are equipped with
Double Data Rate (DDR) interfaces. Each address location is
associated with four 8-bit words (CY7C1541V18), 9-bit words
(CY7C1556V18), 18-bit words (CY7C1543V18), or 36-bit words
(CY7C1545V18) that burst sequentially into or out of the device.
Since data can be transferred into and out of the device on every
rising edge of both input clocks (K and K), memory bandwidth is
maximized while simplifying system design by eliminating bus
“turn-arounds”.
Depth expansion is accomplished with Port Selects for each port.
Port selects allow each port to operate independently.
All synchronous inputs pass through input registers controlled by
the K or K input clocks. All data outputs pass through output
registers controlled by the K or K input clocks. Writes are
conducted with on-chip synchronous self-timed write circuitry.
Selection Guide
375 MHz
Maximum Operating Frequency
Maximum Operating Current
x8
333 MHz
300 MHz
Unit
375
333
300
MHz
1300
1200
1100
mA
x9
1300
1200
1100
x18
1300
1200
1100
x36
1370
1230
1140
Note
1. The QDR consortium specification for VDDQ is 1.5V + 0.1V. The Cypress QDR devices exceed the QDR consortium specification and are capable of supporting
VDDQ = 1.4V to VDD.
Cypress Semiconductor Corporation
Document Number: 001-05389 Rev. *E
•
198 Champion Court
•
San Jose, CA 95134-1709
•
408-943-2600
Revised July 24, 2007
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Logic Block Diagram (CY7C1541V18)
DOFF
Address
Register
Read Add. Decode
Write
Reg
2M x 8 Array
K
CLK
Gen.
Write
Reg
2M x 8 Array
K
Write
Reg
2M x 8 Array
Address
Register
Write
Reg
2M x 8 Array
A(20:0)
21
8
Write Add. Decode
D[7:0]
Control
Logic
21
A(20:0)
RPS
Read Data Reg.
CQ
32
VREF
WPS
NWS[1:0]
16
Control
Logic
Reg.
16
Reg.
CQ
Reg. 8
8
8
8
8
Q[7:0]
QVLD
Logic Block Diagram (CY7C1556V18)
DOFF
Address
Register
Read Add. Decode
Write
Reg
2M x 9 Array
K
CLK
Gen.
Write
Reg
2M x 9 Array
K
Write
Reg
2M x 9 Array
Address
Register
Write
Reg
2M x 9 Array
A(20:0)
21
9
Write Add. Decode
D[8:0]
Control
Logic
21
A(20:0)
RPS
Read Data Reg.
CQ
36
VREF
WPS
BWS[0]
18
Control
Logic
18
Reg.
Reg.
Reg. 9
9
9
9
CQ
9
Q[8:0]
QVLD
Document Number: 001-05389 Rev. *E
Page 2 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Logic Block Diagram (CY7C1543V18)
DOFF
Address
Register
Read Add. Decode
Write
Reg
1M x 18 Array
K
CLK
Gen.
Write
Reg
1M x 18 Array
K
Write
Reg
1M x 18 Array
Address
Register
Write
Reg
1M x 18 Array
A(19:0)
20
18
Write Add. Decode
D[17:0]
Control
Logic
20
A(19:0)
RPS
Read Data Reg.
CQ
72
VREF
WPS
BWS[1:0]
36
Control
Logic
Reg.
36
Reg.
CQ
Reg. 18
18
18
18
18
Q[17:0]
QVLD
Logic Block Diagram (CY7C1545V18)
DOFF
Address
Register
Read Add. Decode
Write
Reg
512K x 36 Array
K
CLK
Gen.
Write
Reg
512K x 36 Array
K
Write
Reg
512K x 36 Array
Address
Register
Write
Reg
512K x 36 Array
A(18:0)
19
36
Write Add. Decode
D[35:0]
Control
Logic
19
A(18:0)
RPS
Read Data Reg.
CQ
144
VREF
WPS
BWS[3:0]
72
Control
Logic
72
Reg.
Reg.
Reg. 36
36
36
36
CQ
36
Q[35:0]
QVLD
Document Number: 001-05389 Rev. *E
Page 3 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Pin Configuration
The Pin Configuration for CY7C1541V18, CY7C1556V18, CY7C1543V18, and CY7C1545V18 follows.[2]
165-Ball FBGA (15 x 17 x 1.4 mm) Pinout
CY7C1541V18 (8M x 8)
A
1
2
3
4
5
6
7
8
9
10
11
CQ
A
A
WPS
NWS1
K
NC/144M
RPS
A
A
CQ
B
NC
NC
NC
A
NC/288M
K
NWS0
A
NC
NC
Q3
C
NC
NC
NC
VSS
A
NC
A
VSS
NC
NC
D3
D
NC
D4
NC
VSS
VSS
VSS
VSS
VSS
NC
NC
NC
E
NC
NC
Q4
VDDQ
VSS
VSS
VSS
VDDQ
NC
D2
Q2
F
NC
NC
NC
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
NC
G
NC
D5
Q5
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
NC
H
DOFF
VREF
VDDQ
VDDQ
VDD
VSS
VDD
VDDQ
VDDQ
VREF
ZQ
J
NC
NC
NC
VDDQ
VDD
VSS
VDD
VDDQ
NC
Q1
D1
K
NC
NC
NC
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
NC
L
NC
Q6
D6
VDDQ
VSS
VSS
VSS
VDDQ
NC
NC
Q0
M
NC
NC
NC
VSS
VSS
VSS
VSS
VSS
NC
NC
D0
N
NC
D7
NC
VSS
A
A
A
VSS
NC
NC
NC
P
NC
NC
Q7
A
A
QVLD
A
A
NC
NC
NC
R
TDO
TCK
A
A
A
NC
A
A
A
TMS
TDI
CY7C1556V18 (8M x 9)
1
2
3
4
5
6
7
8
9
10
11
A
CQ
A
A
WPS
NC
K
NC/144M
RPS
A
A
CQ
B
NC
NC
NC
A
NC/288M
K
BWS0
A
NC
NC
Q4
C
NC
NC
NC
VSS
A
NC
A
VSS
NC
NC
D4
D
NC
D5
NC
VSS
VSS
VSS
VSS
VSS
NC
NC
NC
E
NC
NC
Q5
VDDQ
VSS
VSS
VSS
VDDQ
NC
D3
Q3
F
NC
NC
NC
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
NC
G
NC
D6
Q6
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
NC
H
DOFF
VREF
VDDQ
VDDQ
VDD
VSS
VDD
VDDQ
VDDQ
VREF
ZQ
J
NC
NC
NC
VDDQ
VDD
VSS
VDD
VDDQ
NC
Q2
D2
K
NC
NC
NC
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
NC
L
NC
Q7
D7
VDDQ
VSS
VSS
VSS
VDDQ
NC
NC
Q1
M
NC
NC
NC
VSS
VSS
VSS
VSS
VSS
NC
NC
D1
N
NC
D8
NC
VSS
A
A
A
VSS
NC
NC
NC
P
NC
NC
Q8
A
A
QVLD
A
A
NC
D0
Q0
R
TDO
TCK
A
A
A
NC
A
A
A
TMS
TDI
Note
2. NC/144M and NC/288M are not connected to the die and can be tied to any voltage level.
Document Number: 001-05389 Rev. *E
Page 4 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Pin Configuration
The Pin Configuration for CY7C1541V18, CY7C1556V18, CY7C1543V18, and CY7C1545V18 follows.[2] (continued)
165-Ball FBGA (15 x 17 x 1.4 mm) Pinout
CY7C1543V18 (4M x 18)
A
1
2
3
4
5
6
7
8
9
10
11
CQ
NC/144M
A
WPS
BWS1
K
NC/288M
RPS
A
A
CQ
B
NC
Q9
D9
A
NC
K
BWS0
A
NC
NC
Q8
C
NC
NC
D10
VSS
A
NC
A
VSS
NC
Q7
D8
D
NC
D11
Q10
VSS
VSS
VSS
VSS
VSS
NC
NC
D7
E
NC
NC
Q11
VDDQ
VSS
VSS
VSS
VDDQ
NC
D6
Q6
F
NC
Q12
D12
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
Q5
G
NC
D13
Q13
VDDQ
VDD
VSS
VDD
VDDQ
NC
NC
D5
H
DOFF
VREF
VDDQ
VDDQ
VDD
VSS
VDD
VDDQ
VDDQ
VREF
ZQ
J
NC
NC
D14
VDDQ
VDD
VSS
VDD
VDDQ
NC
Q4
D4
K
NC
NC
Q14
VDDQ
VDD
VSS
VDD
VDDQ
NC
D3
Q3
L
NC
Q15
D15
VDDQ
VSS
VSS
VSS
VDDQ
NC
NC
Q2
M
NC
NC
D16
VSS
VSS
VSS
VSS
VSS
NC
Q1
D2
N
NC
D17
Q16
VSS
A
A
A
VSS
NC
NC
D1
P
NC
NC
Q17
A
A
QVLD
A
A
NC
D0
Q0
R
TDO
TCK
A
A
A
NC
A
A
A
TMS
TDI
CY7C1545V18 (4M x 36)
1
2
3
4
5
6
7
8
9
10
11
A
CQ
NC/288M
A
WPS
BWS2
K
BWS1
RPS
A
NC/144M
CQ
B
Q27
Q18
D18
A
BWS3
K
BWS0
A
D17
Q17
Q8
C
D27
Q28
D19
VSS
A
NC
A
VSS
D16
Q7
D8
D
D28
D20
Q19
VSS
VSS
VSS
VSS
VSS
Q16
D15
D7
E
Q29
D29
Q20
VDDQ
VSS
VSS
VSS
VDDQ
Q15
D6
Q6
F
Q30
Q21
D21
VDDQ
VDD
VSS
VDD
VDDQ
D14
Q14
Q5
G
D30
D22
Q22
VDDQ
VDD
VSS
VDD
VDDQ
Q13
D13
D5
H
DOFF
VREF
VDDQ
VDDQ
VDD
VSS
VDD
VDDQ
VDDQ
VREF
ZQ
J
D31
Q31
D23
VDDQ
VDD
VSS
VDD
VDDQ
D12
Q4
D4
K
Q32
D32
Q23
VDDQ
VDD
VSS
VDD
VDDQ
Q12
D3
Q3
L
Q33
Q24
D24
VDDQ
VSS
VSS
VSS
VDDQ
D11
Q11
Q2
M
D33
Q34
D25
VSS
VSS
VSS
VSS
VSS
D10
Q1
D2
N
D34
D26
Q25
VSS
A
A
A
VSS
Q10
D9
D1
P
Q35
D35
Q26
A
A
QVLD
A
A
Q9
D0
Q0
R
TDO
TCK
A
A
A
NC
A
A
A
TMS
TDI
Document Number: 001-05389 Rev. *E
Page 5 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Pin Definitions
Pin Name
IO
Pin Description
D[x:0]
InputData input signals. Sampled on the rising edge of K and K clocks during valid write operations.
Synchronous CY7C1541V18 − D[7:0]
CY7C1556V18 − D[8:0]
CY7C1543V18 − D[17:0]
CY7C1545V18 − D[35:0]
WPS
InputWrite Port Select, Active LOW. Sampled on the rising edge of the K clock. When asserted active,
Synchronous a write operation is initiated. Deasserting deselects the Write Port. Deselecting the Write Port causes
D[x:0] to be ignored.
NWS0, NWS1,
InputNibble Write Select 0, 1, Active LOW (CY7C1541V18 Only). Sampled on the rising edge of the K
Synchronous and K clocks when write operations are active. Used to select which nibble is written into the device
during the current portion of the write operations. NWS0 controls D[3:0] and NWS1 controls D[7:4].
All the nibble Write Selects are sampled on the same edge as the data. The corresponding nibble of
data is ignored by deselecting a nibble write select and is not written into the device.
BWS0, BWS1,
BWS2, BWS3
InputByte Write Select 0, 1, 2 and 3 - Active LOW. Sampled on the rising edge of the K and K clocks
Synchronous during write operations. Used to select which byte is written into the device during the current portion
of the write operations. Bytes not written remain unaltered.
CY7C1556V18 − BWS0 controls D[8:0]
CY7C1543V18 − BWS0 controls D[8:0] and BWS1 controls D[17:9].
CY7C1545V18 − BWS0 controls D[8:0], BWS1 controls D[17:9], BWS2 controls D[26:18] and BWS3
controls D[35:27].
All the Byte Write Selects are sampled on the same edge as the data. Deselecting a Byte Write Select
causes the corresponding byte of data to be ignored and not written into the device.
A
InputAddress Inputs. Sampled on the rising edge of the K clock during active read and write operations.
Synchronous These address inputs are multiplexed for both read and write operations. Internally, the device is
organized as 8M x 8 (4 arrays each of 2M x 8) for CY7C1541V18, 8M x 9 (4 arrays each of 2M x 9)
for CY7C1556V18, 4M x 18 (4 arrays each of 1M x 18) for CY7C1543V18 and 2M x 36 (4 arrays
each of 512K x 36) for CY7C1545V18. Therefore, only 21 address inputs are needed to access the
entire memory array of CY7C1541V18 and CY7C1556V18, 20 address inputs for CY7C1543V18,
and 19 address inputs for CY7C1545V18. These inputs are ignored when the appropriate port is
deselected.
Q[x:0]
OutputsData Output signals. These pins drive out the requested data during a read operation. Valid data is
Synchronous driven out on the rising edge of both the K and K clocks during read operations or K and K. When
the Read Port is deselected, Q[x:0] are automatically tri-stated.
CY7C1541V18 − Q[7:0]
CY7C1556V18 − Q[8:0]
CY7C1543V18 − Q[17:0]
CY7C1545V18 − Q[35:0]
RPS
InputRead Port Select, Active LOW. Sampled on the rising edge of Positive Input Clock (K). When active,
Synchronous a read operation is initiated. Deasserting causes the Read Port to be deselected. When deselected,
the pending access is allowed to complete and the output drivers are automatically tri-stated following
the next rising edge of the K clock. Each read access consists of a burst of four sequential transfers.
QVLD
Valid output
indicator
Valid Output Indicator. The Q Valid indicates valid output data. QVLD is edge aligned with CQ and
CQ.
K
InputClock
Positive Input Clock Input. The rising edge of K is used to capture synchronous inputs to the device
and to drive out data through Q[x:0] when in single clock mode. All accesses are initiated on the rising
edge of K.
K
InputClock
Negative Input Clock Input. K is used to capture synchronous inputs being presented to the device
and to drive out data through Q[x:0] when in single clock mode.
Echo Clock
Synchronous Echo Clock Outputs. This is a free running clock and is synchronized to the input
clock (K) of the QDR-II+. The timings for the echo clocks are shown in “Switching Characteristics”
on page 22.
CQ
Document Number: 001-05389 Rev. *E
Page 6 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Pin Definitions
Pin Name
(continued)
IO
Pin Description
CQ
Echo Clock
Synchronous Echo Clock Outputs. This is a free running clock and is synchronized to the input
clock (K) of the QDR-II+. The timings for the echo clocks are shown in “Switching Characteristics”
on page 22.
ZQ
Input
Output Impedance Matching Input. This input is used to tune the device outputs to the system data
bus impedance. CQ, CQ and Q[x:0] output impedance are set to 0.2 x RQ, where RQ is a resistor
connected between ZQ and ground. Alternately, this pin can be connected directly to VDDQ, which
enables the minimum impedance mode. This pin cannot be connected directly to GND or left unconnected.
DOFF
Input
DLL Turn Off-Active LOW. Connecting this pin to ground turns off the DLL inside the device.The
timings in the DLL turned off operation are different from those listed in this data sheet. For normal
operation, this pin can be connected to a pull up through a 10 KΩ or less pull up resistor. The device
behaves in QDR-I mode when the DLL is turned off. In this mode, the device can be operated at a
frequency of up to 167 MHz with QDR-I timing.
TDO
Output
TCK
Input
TCK pin for JTAG.
TDI
Input
TDI pin for JTAG.
TMS
Input
TMS pin for JTAG.
NC
N/A
Not connected to the die. Can be tied to any voltage level.
NC/144M
N/A
Not connected to the die. Can be tied to any voltage level.
NC/288M
N/A
Not connected to the die. Can be tied to any voltage level.
VREF
VDD
VSS
VDDQ
InputReference
TDO for JTAG.
Reference Voltage Input. Static input used to set the reference level for HSTL inputs and Outputs
as well as AC measurement points.
Power Supply Power supply inputs to the core of the device.
Ground
Ground for the device.
Power Supply Power supply inputs for the outputs of the device.
Functional Overview
The CY7C1541V18, CY7C1556V18, CY7C1543V18, and
CY7C1545V18 are synchronous pipelined Burst SRAMs
equipped with both a Read Port and a Write Port. The Read Port
is dedicated to read operations and the Write Port is dedicated
to write operations. Data flows into the SRAM through the Write
Port and out through the Read Port. These devices multiplex the
address inputs in order to minimize the number of address pins
required. By having separate Read and Write Ports, the QDR-II+
completely eliminates the need to “turn-around” the data bus and
avoids any possible data contention, thereby simplifying system
design. Each access consists of four 8-bit data transfers in the
case of CY7C1541V18, four 9-bit data transfers in the case of
CY7C1556V18, four 18-bit data transfers in the case of
CY7C1543V18, and four 36-bit data transfers in the case of
CY7C1545V18, in two clock cycles.
Accesses for both ports are initiated on the Positive Input Clock
(K). All synchronous input and output timing are referenced from
the rising edge of the input clocks (K and K).
All synchronous data inputs (D[x:0]) inputs pass through input
registers controlled by the input clocks (K and K). All
synchronous data outputs (Q[x:0]) outputs pass through output
Document Number: 001-05389 Rev. *E
registers controlled by the rising edge of the input clocks (K and
K) as well.
All synchronous control (RPS, WPS, BWS[x:0]) inputs pass
through input registers controlled by the rising edge of the input
clocks (K and K).
CY7C1543V18 is described in the following sections. The same
basic descriptions apply to CY7C1541V18, CY7C1556V18, and
CY7C1545V18.
Read Operations
The CY7C1543V18 is organized internally as 4 arrays of 1M x
18. Accesses are completed in a burst of four sequential 18-bit
data words. Read operations are initiated by asserting RPS
active at the rising edge of the Positive Input Clock (K). The
address presented to address inputs are stored in the Read
Address register. Following the next two K clock rise, the corresponding lowest order 18-bit word of data is driven onto the
Q[17:0] using K as the output timing reference. On the subsequent rising edge of K the next 18-bit data word is driven onto
the Q[17:0]. This process continues until all four 18-bit data words
have been driven out onto Q[17:0]. The requested data is valid
0.45*ns from the rising edge of the input clock (K or K). In order
to maintain the internal logic, each read access must be allowed
to complete. Each read access consists of four 18-bit data words
Page 7 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
and takes 2 clock cycles to complete. Therefore, read accesses
to the device can not be initiated on two consecutive K clock
rises. The internal logic of the device ignores the second read
request. Read accesses can be initiated on every other K clock
rise. Doing so pipelines the data flow such that data is transferred
out of the device on every rising edge of the input clocks (K and
K).
When the Read Port is deselected, the CY7C1543V18 first
completes the pending read transactions. Synchronous internal
circuitry automatically tri-states the outputs following the next
rising edge of the Positive Input Clock (K). This allows for a
seamless transition between devices without the insertion of wait
states in a depth expanded memory.
Write Operations
Write operations are initiated by asserting WPS active at the
rising edge of the Positive Input Clock (K). On the following K
clock rise the data presented to D[17:0] is latched and stored into
the lower 18-bit Write Data register, provided BWS[1:0] are both
asserted active. On the subsequent rising edge of the Negative
Input Clock (K) the information presented to D[17:0] is also stored
into the Write Data register, provided BWS[1:0] are both asserted
active. This process continues for one more cycle until four 18-bit
words (a total of 72 bits) of data are stored in the SRAM. The 72
bits of data are then written into the memory array at the specified
location. Therefore, write accesses to the device can not be
initiated on two consecutive K clock rises. The internal logic of
the device ignores the second write request. Write accesses can
be initiated on every other rising edge of the Positive Input Clock
(K). Doing so pipelines the data flow such that 18 bits of data can
be transferred into the device on every rising edge of the input
clocks (K and K).
When deselected, the Write Port ignores all inputs after the
pending write operations have been completed.
Byte Write Operations
Byte Write operations are supported by the CY7C1543V18. A
write operation is initiated as described in the Write Operations
section above. The bytes that are written are determined by
BWS0 and BWS1, which are sampled with each set of 18-bit data
words. Asserting the appropriate Byte Write Select input during
the data portion of a write allows the data being presented to be
latched and written into the device. Deasserting the Byte Write
Select input during the data portion of a write allows the data
stored in the device for that byte to remain unaltered. This feature
can be used to simplify Read/Modify/Write operations to a Byte
Write operation.
Concurrent Transactions
The Read and Write Ports on the CY7C1543V18 operate
completely independently of one another. Since each port
latches the address inputs on different clock edges, the user can
read or write to any location, regardless of the transaction on the
other port. If the ports access the same location when a read
follows a write in successive clock cycles, the SRAM delivers the
most recent information associated with the specified address
location. This includes forwarding data from a write cycle that
was initiated on the previous K clock rise.
selected on the same K clock rise, the arbitration depends on the
previous state of the SRAM. If both ports were deselected, the
Read Port takes priority. If a read was initiated on the previous
cycle, the Write Port assumes priority (since read operations can
not be initiated on consecutive cycles). If a write was initiated on
the previous cycle, the Read Port assumes priority (since write
operations can not be initiated on consecutive cycles).
Therefore, asserting both port selects active from a deselected
state results in alternating read and write operations being
initiated, with the first access being a read.
Depth Expansion
The CY7C1543V18 has a Port Select input for each port. This
allows for easy depth expansion. Both Port Selects are sampled
on the rising edge of the Positive Input Clock only (K). Each port
select input can deselect the specified port. Deselecting a port
does not affect the other port. All pending transactions (read and
write) are completed prior to the device being deselected.
Programmable Impedance
An external resistor, RQ, must be connected between the ZQ pin
on the SRAM and VSS to allow the SRAM to adjust its output
driver impedance. The value of RQ must be 5X the value of the
intended line impedance driven by the SRAM, The allowable
range of RQ to guarantee impedance matching with a tolerance
of ±15% is between 175Ω and 350Ω, with VDDQ = 1.5V. The
output impedance is adjusted every 1024 cycles upon powerup
to account for drifts in supply voltage and temperature.
Echo Clocks
Echo clocks are provided on the QDR-II+ to simplify data capture
on high speed systems. Two echo clocks are generated by the
QDR-II+. CQ is referenced with respect to K and CQ is referenced with respect to K. These are free running clocks and are
synchronized to the input clock of the QDR-II+. The timings for
the echo clocks are shown in “Switching Characteristics” on
page 22.
Valid Data Indicator (QVLD)
QVLD is provided on the QDR-II+ to simplify data capture on high
speed systems. The QVLD is generated by the QDR-II+ device
along with Data output. This signal is also edge-aligned with the
echo clock and follows the timing of any data pin. This signal is
asserted half a cycle before valid data arrives.
DLL
These chips utilize a Delay Lock Loop (DLL) that is designed to
function between 120 MHz and the specified maximum clock
frequency. The DLL may be disabled by applying ground to the
DOFF pin. When the DLL is turned off, the device behaves in
DDR-I mode (with 1.0 cycle latency and a longer access time).
For more information, refer to the application note, “DLL Considerations in QDRII/DDRII/QDRII+/DDRII+”. The DLL can also be
reset by slowing or stopping the input clocks K and K for a
minimum of 30ns. However, it is not necessary for the DLL to be
reset in order to lock to the desired frequency. During Power up,
when the DOFF is tied HIGH, the DLL gets locked after 2048
cycles of stable clock.
Read accesses and write access must be scheduled such that
one transaction is initiated on any clock cycle. If both ports are
Document Number: 001-05389 Rev. *E
Page 8 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Application Example
Figure 1 shows four QDR-II+ used in an application.
Figure 1. Application Example
ZQ
CQ/CQ
SRAM #1
Q
D
A RPS WPS BWS K K
Vt
R
RQ = 250ohms
ZQ
CQ/CQ
SRAM #4
Q
K
K
BWS
RPS WPS
D
A
DATA IN
DATA OUT
Address
R
R
BUS MASTER RPS
(CPU or ASIC) WPS
RQ = 250ohms
Vt
Vt
BWS
CLKIN/CLKIN
Source K
Source K
R = 50ohms, Vt = VDDQ /2
Truth Table
The truth table for CY7C1541V18, CY7C1556V18, CY7C1543V18, and CY7C1545V18 follows.[3, 4, 5, 6, 7, 8]
Operation
K
RPS WPS
DQ
DQ
DQ
DQ
L-H
Write Cycle:
Load address on the rising
edge of K; input write data
on two consecutive K and
K rising edges.
H[9]
L[10]
D(A) at K(t + 1) ↑ D(A + 1) at K(t +1) ↑ D(A + 2) at K(t + 2) ↑ D(A + 3) at K(t + 2) ↑
Read Cycle:
L-H
(2.0 cycle Latency)
Load address on the rising
edge of K; wait two cycles;
read data on two consecutive K and K rising edges.
L[10]
X
Q(A) at K(t + 2) ↑ Q(A + 1) at K(t + 2) ↑ Q(A + 2) at K(t + 3) ↑ Q(A + 3) at K(t + 3) ↑
NOP: No Operation
L-H
H
H
D=X
Q = High-Z
D=X
Q = High-Z
D=X
Q = High-Z
D=X
Q = High-Z
Standby: Clock Stopped
Stopped X
X
Previous State
Previous State
Previous State
Previous State
Notes
3. X = “Don't Care,” H = Logic HIGH, L = Logic LOW, ↑represents rising edge.
4. Device powers up deselected with the outputs in a tri-state condition.
5. “A” represents address location latched by the devices when transaction was initiated. A + 1, A + 2, and A +3 represents the address sequence in the burst.
6. “t” represents the cycle at which a read/write operation is started. t + 1, t + 2, and t + 3 are the first, second and third clock cycles respectively succeeding the “t” clock cycle.
7. Data inputs are registered at K and K rising edges. Data outputs are delivered on K and K rising edges, also.
8. It is recommended that K = K = HIGH when clock is stopped. This is not essential, but permits most rapid restart by overcoming transmission line charging symmetrically.
9. If this signal was LOW to initiate the previous cycle, this signal becomes a “Don’t Care” for this operation.
10. This signal was HIGH on previous K clock rise. Initiating consecutive read or write operations on consecutive K clock rises is not permitted. The device ignores the
second read or write request.
Document Number: 001-05389 Rev. *E
Page 9 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Write Cycle Descriptions
The write cycle description table for CY7C1541V18 and CY7C1543V18 follows. [3, 11]
BWS0/ BWS1/
K
K
L
L–H
–
L
L
–
L
H
L–H
L
H
–
H
L
L–H
H
L
–
H
H
L–H
H
H
–
NWS0
NWS1
L
Comments
During the data portion of a write sequence :
CY7C1541V18 − both nibbles (D[7:0]) are written into the device,
CY7C1543V18 − both bytes (D[17:0]) are written into the device.
L-H During the data portion of a write sequence :
CY7C1541V18 − both nibbles (D[7:0]) are written into the device,
CY7C1543V18 − both bytes (D[17:0]) are written into the device.
–
During the data portion of a write sequence :
CY7C1541V18 − only the lower nibble (D[3:0]) is written into the device, D[7:4] remains unaltered.
CY7C1543V18 − only the lower byte (D[8:0]) is written into the device, D[17:9] remains unaltered.
L–H During the data portion of a write sequence :
CY7C1541V18 − only the lower nibble (D[3:0]) is written into the device, D[7:4] remains unaltered.
CY7C1543V18 − only the lower byte (D[8:0]) is written into the device, D[17:9] remains unaltered.
–
During the data portion of a write sequence :
CY7C1541V18 − only the upper nibble (D[7:4]) is written into the device, D[3:0] remains unaltered.
CY7C1543V18 − only the upper byte (D[17:9]) is written into the device, D[8:0] remains unaltered.
L–H During the data portion of a write sequence :
CY7C1541V18 − only the upper nibble (D[7:4]) is written into the device, D[3:0] remains unaltered.
CY7C1543V18 − only the upper byte (D[17:9]) is written into the device, D[8:0] remains unaltered.
–
No data is written into the devices during this portion of a write operation.
L–H No data is written into the devices during this portion of a write operation.
Write Cycle Descriptions
The write cycle description table for CY7C1556V18 follows. [3, 11]
BWS0
K
K
L
L–H
–
During the Data portion of a write sequence, the single byte (D[8:0]) is written into the device.
L
–
L–H
During the Data portion of a write sequence, the single byte (D[8:0]) is written into the device.
H
L–H
–
No data is written into the device during this portion of a write operation.
H
–
L–H
No data is written into the device during this portion of a write operation.
Note
11. Assumes a write cycle was initiated per the Write Cycle Descriptions table. NWS0, NWS1, BWS0, BWS1, BWS2, and BWS3 can be altered on different portions of a
write cycle, as long as the setup and hold requirements are achieved.
Document Number: 001-05389 Rev. *E
Page 10 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Write Cycle Descriptions
The write cycle description table for CY7C1545V18 follows. [3, 11]
BWS0
BWS1
BWS2
BWS3
K
K
Comments
L
L
L
L
L–H
–
During the Data portion of a write sequence, all four bytes (D[35:0]) are written into
the device.
L
L
L
L
–
L
H
H
H
L–H
L
H
H
H
–
H
L
H
H
L–H
H
L
H
H
–
H
H
L
H
L–H
H
H
L
H
–
H
H
H
L
L–H
H
H
H
L
–
H
H
H
H
L–H
H
H
H
H
–
Document Number: 001-05389 Rev. *E
L–H During the Data portion of a write sequence, all four bytes (D[35:0]) are written into
the device.
–
During the Data portion of a write sequence, only the lower byte (D[8:0]) is written
into the device. D[35:9] remains unaltered.
L–H During the Data portion of a write sequence, only the lower byte (D[8:0]) is written
into the device. D[35:9] remains unaltered.
–
During the Data portion of a write sequence, only the byte (D[17:9]) is written into
the device. D[8:0] and D[35:18] remains unaltered.
L–H During the Data portion of a write sequence, only the byte (D[17:9]) is written into
the device. D[8:0] and D[35:18] remains unaltered.
–
During the Data portion of a write sequence, only the byte (D[26:18]) is written into
the device. D[17:0] and D[35:27] remains unaltered.
L–H During the Data portion of a write sequence, only the byte (D[26:18]) is written into
the device. D[17:0] and D[35:27] remains unaltered.
–
During the Data portion of a write sequence, only the byte (D[35:27]) is written into
the device. D[26:0] remains unaltered.
L–H During the Data portion of a write sequence, only the byte (D[35:27]) is written into
the device. D[26:0] remains unaltered.
–
No data is written into the device during this portion of a write operation.
L–H No data is written into the device during this portion of a write operation.
Page 11 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
IEEE 1149.1 Serial Boundary Scan (JTAG)
These SRAMs incorporate a serial boundary scan test access
port (TAP) in the FBGA package. This part is fully compliant with
IEEE Standard #1149.1-2001. The TAP operates using JEDEC
standard 1.8V IO logic levels.
Disabling the JTAG Feature
It is possible to operate the SRAM without using the JTAG
feature. To disable the TAP controller, TCK must be tied LOW
(VSS) to prevent clocking of the device. TDI and TMS are internally pulled up and may be unconnected. They may alternately
be connected to VDD through a pull up resistor. TDO must be left
unconnected. Upon power up, the device comes up in a reset
state which does not interfere with the operation of the device.
Instruction Register
Three-bit instructions can be serially loaded into the instruction
register. This register is loaded when it is placed between the TDI
and TDO pins as shown in “TAP Controller Block Diagram” on
page 15. Upon power up, the instruction register is loaded with
the IDCODE instruction. It is also loaded with the IDCODE
instruction if the controller is placed in a reset state as described
in the previous section.
When the TAP controller is in the Capture IR state, the two least
significant bits are loaded with a binary “01” pattern to allow for
fault isolation of the board level serial test path.
Bypass Register
The test clock is used only with the TAP controller. All inputs are
captured on the rising edge of TCK. All outputs are driven from
the falling edge of TCK.
To save time when serially shifting data through registers, it is
sometimes advantageous to skip certain chips. The bypass
register is a single-bit register that can be placed between TDI
and TDO pins. This allows data to be shifted through the SRAM
with minimal delay. The bypass register is set LOW (VSS) when
the BYPASS instruction is executed.
Test Mode Select
Boundary Scan Register
Test Access Port–Test Clock
The TMS input is used to give commands to the TAP controller
and is sampled on the rising edge of TCK. It is allowable to leave
this pin unconnected if the TAP is not used. The pin is pulled up
internally, resulting in a logic HIGH level.
Test Data-In (TDI)
The TDI pin is used to serially input information into the registers
and can be connected to the input of any of the registers. The
register between TDI and TDO is chosen by the instruction that
is loaded into the TAP instruction register. For information on
loading the instruction register, see the “TAP Controller State
Diagram” on page 14. TDI is internally pulled up and can be
unconnected if the TAP is unused in an application. TDI is
connected to the most significant bit (MSB) on any register.
The boundary scan register is connected to all of the input and
output pins on the SRAM. Several no connect (NC) pins are also
included in the scan register to reserve pins for higher density
devices.
The boundary scan register is loaded with the contents of the
RAM Input and Output ring when the TAP controller is in the
Capture-DR state and is then placed between the TDI and TDO
pins when the controller is moved to the Shift-DR state. The
EXTEST, SAMPLE/PRELOAD and SAMPLE Z instructions can
be used to capture the contents of the Input and Output ring.
“Boundary Scan Order” on page 18 show the order in which the
bits are connected. Each bit corresponds to one of the bumps on
the SRAM package. The MSB of the register is connected to TDI,
and the LSB is connected to TDO.
Test Data-Out (TDO)
Identification (ID) Register
The TDO output pin is used to serially clock data-out from the
registers. The output is active depending upon the current state
of the TAP state machine (see “Instruction Codes” on page 17).
The output changes on the falling edge of TCK. TDO is
connected to the least significant bit (LSB) of any register.
The ID register is loaded with a vendor-specific, 32-bit code
during the Capture-DR state when the IDCODE command is
loaded in the instruction register. The IDCODE is hardwired into
the SRAM and can be shifted out when the TAP controller is in
the Shift-DR state. The ID register has a vendor code and other
information described in the “Identification Register Definitions”
on page 17.
Performing a TAP Reset
A Reset is performed by forcing TMS HIGH (VDD) for five rising
edges of TCK. This RESET does not affect the operation of the
SRAM and may be performed while the SRAM is operating. At
power up, the TAP is reset internally to ensure that TDO comes
up in a high-Z state.
TAP Registers
Registers are connected between the TDI and TDO pins and
allow data to be scanned into and out of the SRAM test circuitry.
Only one register can be selected at a time through the
instruction registers. Data is serially loaded into the TDI pin on
the rising edge of TCK. Data is output on the TDO pin on the
falling edge of TCK.
Document Number: 001-05389 Rev. *E
TAP Instruction Set
Eight different instructions are possible with the three-bit
instruction register. All combinations are listed in the “Instruction
Codes” on page 17. Three of these instructions are listed as
RESERVED and must not be used. The other five instructions
are described in detail below.
Instructions are loaded into the TAP controller during the Shift-IR
state when the instruction register is placed between TDI and
TDO. During this state, instructions are shifted through the
instruction register through the TDI and TDO pins. To execute
the instruction once it is shifted in, the TAP controller needs to be
moved into the Update-IR state.
Page 12 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
IDCODE
The IDCODE instruction causes a vendor-specific, 32-bit code
to be loaded into the instruction register. It also places the
instruction register between the TDI and TDO pins and allows
the IDCODE to be shifted out of the device when the TAP
controller enters the Shift-DR state. The IDCODE instruction is
loaded into the instruction register upon power up or whenever
the TAP controller is given a test logic reset state.
SAMPLE Z
The SAMPLE Z instruction causes the boundary scan register to
be connected between the TDI and TDO pins when the TAP
controller is in a Shift-DR state. The SAMPLE Z command puts
the output bus into a High-Z state until the next command is given
during the “Update IR” state.
SAMPLE/PRELOAD
SAMPLE/PRELOAD is a 1149.1 mandatory instruction. When
the SAMPLE/PRELOAD instructions are loaded into the
instruction register and the TAP controller is in the Capture-DR
state, a snapshot of data on the inputs and output pins is
captured in the boundary scan register.
The user must be aware that the TAP controller clock can only
operate at a frequency up to 20 MHz, while the SRAM clock
operates more than an order of magnitude faster. Because there
is a large difference in the clock frequencies, it is possible that
during the Capture-DR state, an input or output undergoes a
transition. The TAP may then try to capture a signal while in
transition (metastable state). This does not harm the device, but
there is no guarantee what value is captured. Repeatable results
may not be possible.
PRELOAD allows an initial data pattern to be placed at the
latched parallel outputs of the boundary scan register cells prior
to the selection of another boundary scan test operation.
The shifting of data for the SAMPLE and PRELOAD phases can
occur concurrently when required—that is, while data captured
is shifted out, the preloaded data can be shifted in.
BYPASS
When the BYPASS instruction is loaded in the instruction register
and the TAP is placed in a Shift-DR state, the bypass register is
placed between the TDI and TDO pins. The advantage of the
BYPASS instruction is that it shortens the boundary scan path
when multiple devices are connected together on a board.
EXTEST
The EXTEST instruction enables the preloaded data to be driven
out through the system output pins. This instruction also selects
the boundary scan register to be connected for serial access
between the TDI and TDO in the shift-DR controller state.
EXTEST OUTPUT BUS TRI-STATE
IEEE Standard 1149.1 mandates that the TAP controller be able
to put the output bus into a tri-state mode.
The boundary scan register has a special bit located at bit #108.
When this scan cell, called the “extest output bus tri-state”, is
latched into the preload register during the Update-DR state in
the TAP controller, it directly controls the state of the output
(Q-bus) pins, when the EXTEST is entered as the current
instruction. When HIGH, it enables the output buffers to drive the
output bus. When LOW, this bit places the output bus into a
High-Z condition.
To guarantee that the boundary scan register captures the
correct value of a signal, the SRAM signal must be stabilized
long enough to meet the TAP controller's capture setup plus hold
times (tCS and tCH). The SRAM clock input might not be captured
correctly if there is no way in a design to stop (or slow) the clock
during a SAMPLE/PRELOAD instruction. If this is an issue, it is
still possible to capture all other signals and simply ignore the
value of the CK and CK# captured in the boundary scan register.
This bit can be set by entering the SAMPLE/PRELOAD or
EXTEST command, and then shifting the desired bit into that cell,
during the Shift-DR state. During Update-DR, the value loaded
into that shift-register cell latches into the preload register. When
the EXTEST instruction is entered, this bit directly controls the
output Q-bus pins. Note that this bit is pre-set HIGH to enable
the output when the device is powered-up, and also when the
TAP controller is in the Test-Logic-Reset state.
Once the data is captured, it is possible to shift out the data by
putting the TAP into the Shift-DR state. This places the boundary
scan register between the TDI and TDO pins.
Reserved
Document Number: 001-05389 Rev. *E
These instructions are not implemented but are reserved for
future use. Do not use these instructions.
Page 13 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
TAP Controller State Diagram
The state diagram for the TAP controller follows.[12]
1
TEST-LOGIC
RESET
0
0
TEST-LOGIC/
IDLE
1
1
SELECT
DR-SCAN
SELECT
IR-SCAN
0
0
1
1
CAPTURE-DR
CAPTURE-IR
0
0
0
SHIFT-DR
1
1
EXIT1-DR
1
EXIT1-IR
0
0
PAUSE-DR
0
0
PAUSE-IR
1
1
0
EXIT2-DR
EXIT2-IR
1
1
UPDATE-DR
1
0
SHIFT-IR
1
0
1
0
UPDATE-IR
1
0
Note
12. The 0/1 next to each state represents the value at TMS at the rising edge of TCK.
Document Number: 001-05389 Rev. *E
Page 14 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
TAP Controller Block Diagram
0
Bypass Register
Selection
Circuitry
TDI
2
1
0
1
0
Instruction Register
31 30 29
.
.
2
Selection
Circuitry
TDO
Identification Register
108 .
.
.
.
2
1
0
Boundary Scan Register
TCK
TMS
TAP Controller
TAP Electrical Characteristics
Over the Operating Range[13, 14, 15]
Parameter
Description
Test Conditions
Min
VOH1
Output HIGH Voltage
IOH = −2.0 mA
1.4
VOH2
Output HIGH Voltage
IOH = −100 µA
1.6
VOL1
Output LOW Voltage
IOL = 2.0 mA
VOL2
Output LOW Voltage
IOL = 100 µA
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
IX
Input and Output Load Current
Max
Unit
V
V
0.4
V
0.2
V
0.65VDD VDD + 0.3
GND ≤ VI ≤ VDD
V
–0.3
0.35VDD
V
–5
5
µA
Notes
13. These characteristics pertain to the TAP inputs (TMS, TCK, TDI and TDO). Parallel load levels are specified in the Electrical Characteristics Table.
14. Overshoot: VIH(AC) < VDDQ + 0.35V (Pulse width less than tCYC/2), Undershoot: VIL(AC) > −0.3V (Pulse width less than tCYC/2).
15. All Voltage referenced to Ground.
Document Number: 001-05389 Rev. *E
Page 15 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
TAP AC Switching Characteristics
Over the Operating Range [16, 17]
Parameter
Description
Min
Max
Unit
20
MHz
tTCYC
TCK Clock Cycle Time
tTF
TCK Clock Frequency
tTH
TCK Clock HIGH
20
ns
tTL
TCK Clock LOW
20
ns
tTMSS
TMS Setup to TCK Clock Rise
5
ns
tTDIS
TDI Setup to TCK Clock Rise
5
ns
tCS
Capture Setup to TCK Rise
5
ns
tTMSH
TMS Hold after TCK Clock Rise
5
ns
tTDIH
TDI Hold after Clock Rise
5
ns
tCH
Capture Hold after Clock Rise
5
ns
50
ns
Setup Times
Hold Times
Output Times
tTDOV
TCK Clock LOW to TDO Valid
tTDOX
TCK Clock LOW to TDO Invalid
10
0
ns
ns
TAP Timing and Test Conditions
Figure 2 shows the TAP timing and test conditions.[17]
Figure 2. TAP Timing and Test Conditions
0.9V
ALL INPUT PULSES
50Ω
1.8V
0.9V
TDO
0V
Z0 = 50Ω
(a)
CL = 20 pF
GND
tTH
tTL
Test Clock
TCK
tTCYC
tTMSH
tTMSS
Test Mode Select
TMS
tTDIS
tTDIH
Test Data In
TDI
Test Data Out
TDO
tTDOV
tTDOX
Notes
16. tCS and tCH refer to the setup and hold time requirements of latching data from the boundary scan register.
17. Test conditions are specified using the load in TAP AC Test Conditions. tR/tF = 1 ns.
Document Number: 001-05389 Rev. *E
Page 16 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Identification Register Definitions
Instruction Field
Value
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
000
000
000
000
Revision Number
(31:29)
Description
Version number.
Cypress Device ID 11010010101000100 11010010101001100 11010010101010100 11010010101100100 Defines the type of
(28:12)
SRAM.
Cypress JEDEC ID
(11:1)
00000110100
00000110100
00000110100
00000110100
1
1
1
1
ID Register
Presence (0)
Allows unique
identification of
SRAM vendor.
Indicates the
presence of an ID
register.
Scan Register Sizes
Register Name
Bit Size
Instruction
3
Bypass
1
ID
32
Boundary Scan
109
Instruction Codes
Instruction
Code
Description
EXTEST
000
Captures the Input/Output ring contents.
IDCODE
001
Loads the ID register with the vendor ID code and places the register between TDI and TDO.
This operation does not affect SRAM operation.
SAMPLE Z
010
Captures the Input/Output contents. Places the boundary scan register between TDI and TDO.
Forces all SRAM output drivers to a High-Z state.
RESERVED
011
Do Not Use: This instruction is reserved for future use.
SAMPLE/PRELOAD
100
Captures the Input/Output ring contents. Places the boundary scan register between TDI and
TDO. Does not affect the SRAM operation.
RESERVED
101
Do Not Use: This instruction is reserved for future use.
RESERVED
110
Do Not Use: This instruction is reserved for future use.
BYPASS
111
Places the bypass register between TDI and TDO. This operation does not affect SRAM
operation.
Document Number: 001-05389 Rev. *E
Page 17 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Boundary Scan Order
Bit #
Bump ID
Bit #
Bump ID
Bit #
Bump ID
Bit #
Bump ID
0
6R
28
10G
56
6A
84
1J
1
6P
29
9G
57
5B
85
2J
2
6N
30
11F
58
5A
86
3K
3
7P
31
11G
59
4A
87
3J
4
7N
32
9F
60
5C
88
2K
5
7R
33
10F
61
4B
89
1K
6
8R
34
11E
62
3A
90
2L
7
8P
35
10E
63
2A
91
3L
8
9R
36
10D
64
1A
92
1M
9
11P
37
9E
65
2B
93
1L
10
10P
38
10C
66
3B
94
3N
3M
11
10N
39
11D
67
1C
95
12
9P
40
9C
68
1B
96
1N
13
10M
41
9D
69
3D
97
2M
14
11N
42
11B
70
3C
98
3P
15
9M
43
11C
71
1D
99
2N
16
9N
44
9B
72
2C
100
2P
17
11L
45
10B
73
3E
101
1P
18
11M
46
11A
74
2D
102
3R
19
9L
47
10A
75
2E
103
4R
20
10L
48
9A
76
1E
104
4P
21
11K
49
8B
77
2F
105
5P
22
10K
50
7C
78
3F
106
5N
23
9J
51
6C
79
1G
107
5R
24
9K
52
8A
80
1F
108
Internal
25
10J
53
7A
81
3G
26
11J
54
7B
82
2G
27
11H
55
6B
83
1H
Document Number: 001-05389 Rev. *E
Page 18 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Power Up Sequence in QDR-II+ SRAM
QDR-II+ SRAMs must be powered up and initialized in a
predefined manner to prevent undefined operations. During
Power Up, when the DOFF is tied HIGH, the DLL gets locked
after 2048 cycles of stable clock.
Power Up Sequence
■
Apply power with DOFF tied HIGH (All other inputs can be
HIGH or LOW)
❐ Apply VDD before VDDQ
❐ Apply VDDQ before VREF or at the same time as VREF
■
Provide stable power and clock (K, K) for 2048 cycles to lock
the DLL.
DLL Constraints
■
DLL uses K clock as its synchronizing input. The input must
have low phase jitter, which is specified as tKC Var.
■
The DLL functions at frequencies down to 120 MHz.
■
If the input clock is unstable and the DLL is enabled, then the
DLL may lock onto an incorrect frequency, causing unstable
SRAM behavior. To avoid this, provide 2048 cycles stable clock
to relock to the desired clock frequency.
~
~
Power Up Waveforms
K
~
~
K
Unstable Clock
> 2048 Stable Clock
Start Normal
Operation
Clock Start (Clock Starts after VDD/VDDQ is Stable)
VDD/VDDQ
DOFF
Document Number: 001-05389 Rev. *E
VDD/VDDQ Stable (< + 0.1V DC per 50 ns)
Fix HIGH (tie to VDDQ)
Page 19 of 28
CY7C1541V18
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CY7C1545V18
Maximum Ratings
Current into Outputs (LOW) ........................................ 20 mA
Exceeding maximum ratings may impair the useful life of the
device. These user guidelines are not tested.
Storage Temperature ................................. –65°C to +150°C
Static Discharge Voltage (MIL-STD-883, M. 3015)... >2001V
Latch-up Current .................................................... >200 mA
Operating Range
Ambient Temperature with Power Applied.. –55°C to +125°C
Supply Voltage on VDD Relative to GND ........–0.5V to +2.9V
Range
Supply Voltage on VDDQ Relative to GND.......–0.5V to +VDD
Commercial
DC Applied to Outputs in High-Z ........ –0.5V to VDDQ + 0.3V
Industrial
[14]
DC Input Voltage
Ambient
Temperature (TA)
VDD[18]
VDDQ[18]
0°C to +70°C
1.8 ± 0.1V
1.4V to
VDD
–40°C to +85°C
............................... –0.5V to VDD + 0.3V
Electrical Characteristics
DC Electrical Characteristics
Over the Operating Range[15]
Parameter
Description
Test Conditions
Min
Typ
Max
Unit
VDD
Power Supply Voltage
1.7
1.8
1.9
V
VDDQ
IO Supply Voltage
1.4
1.5
VDD
V
VOH
Output HIGH Voltage
Note 19
VDDQ/2 – 0.12
VDDQ/2 + 0.12
V
VOL
Output LOW Voltage
Note 20
VDDQ/2 – 0.12
VDDQ/2 + 0.12
V
VOH(LOW)
Output HIGH Voltage
IOH = −0.1 mA, Nominal Impedance
VDDQ – 0.2
VDDQ
V
VOL(LOW)
Output LOW Voltage
IOL = 0.1 mA, Nominal Impedance
VSS
0.2
V
VREF + 0.1
VDDQ + 0.15
V
–0.15
VREF – 0.1
V
Voltage[14]
VIH
Input HIGH
VIL
Input LOW Voltage[14]
IX
Input Leakage Current
GND ≤ VI ≤ VDDQ
−2
2
µA
IOZ
Output Leakage Current
GND ≤ VI ≤ VDDQ, Output Disabled
−2
2
µA
Voltage[21]
VREF
Input Reference
IDD (x8)
VDD Operating Supply
IDD (x9)
IDD (x18)
IDD (x36)
VDD Operating Supply
VDD Operating Supply
VDD Operating Supply
ISB1
Automatic Power down
(x8, x9, X18) Current
Typical Value = 0.75V
0.95
V
VDD = Max,
IOUT = 0 mA,
f = fMAX = 1/tCYC
300 MHz
0.68
0.75
1100
mA
333 MHz
1200
375 MHz
1300
VDD = Max,
IOUT = 0 mA,
f = fMAX = 1/tCYC
300 MHz
1100
333 MHz
1200
375 MHz
1300
VDD = Max,
IOUT = 0 mA,
f = fMAX = 1/tCYC
300 MHz
1100
333 MHz
1200
375 MHz
1300
VDD = Max,
IOUT = 0 mA,
f = fMAX = 1/tCYC
300 MHz
1140
333 MHz
1230
375 MHz
1370
Max VDD,
300 MHz
Both Ports Deselected,
333 MHz
VIN ≥ VIH or VIN ≤ VIL
375
MHz
f = fMAX = 1/tCYC, Inputs Static
450
mA
mA
mA
mA
500
525
Notes
18. Power up: Assumes a linear ramp from 0V to VDD(min) within 200 ms. During this time VIH < VDD and VDDQ < VDD.
19. Output are impedance controlled. IOH = −(VDDQ/2)/(RQ/5) for values of 175 Ω <= RQ <= 350 Ω.
20. Output are impedance controlled. IOL = (VDDQ/2)/(RQ/5) for values of 175 Ω <= RQ <= 350 Ω.
21. VREF (min) = 0.68V or 0.46VDDQ, whichever is larger, VREF (max) = 0.95V or 0.54VDDQ, whichever is smaller.
Document Number: 001-05389 Rev. *E
Page 20 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Electrical Characteristics
(continued)
DC Electrical Characteristics
Over the Operating Range[15]
Parameter
ISB1 (x36)
Description
Test Conditions
Automatic Power down
Current
Min
Typ
Max VDD,
300 MHz
Both Ports Deselected,
333 MHz
VIN ≥ VIH or VIN ≤ VIL
f = fMAX = 1/tCYC, Inputs Static 375 MHz
Max
Unit
385
mA
395
410
AC Electrical Characteristics
Over the Operating Range[14]
Parameter
Description
Test Conditions
Min
Typ
Max
Unit
VIH
Input HIGH Voltage
VREF + 0.2
–
VDDQ + 0.24
V
VIL
Input LOW Voltage
–0.24
–
VREF – 0.2
V
Capacitance
Tested initially and after any design or process change that may affect these parameters.
Parameter
Description
Test Conditions
Max
Unit
5
pF
CIN
Input Capacitance
CCLK
Clock Input Capacitance
6
pF
CO
Output Capacitance
7
pF
Test Conditions
165 FBGA
Package
Unit
Test conditions follow standard test methods and
procedures for measuring thermal impedance, per
EIA/JESD51.
11.82
°C/W
2.33
°C/W
TA = 25°C, f = 1 MHz, VDD = 1.8V, VDDQ = 1.5V
Thermal Resistance
Tested initially and after any design or process change that may affect these parameters.
Parameter
Description
ΘJA
Thermal Resistance
(Junction to Ambient)
ΘJC
Thermal Resistance
(Junction to Case)
AC Test Loads and Waveforms
VREF = 0.75V
VREF
0.75V
VREF
OUTPUT
Z0 = 50Ω
Device
Under
Test
ZQ
RL = 50Ω
VREF = 0.75V
R = 50Ω
ALL INPUT PULSES
1.25V
0.75V
OUTPUT
Device
Under
Test ZQ
RQ =
250Ω
(a)
0.75V
INCLUDING
JIG AND
SCOPE
5 pF
[22]
0.25V
Slew Rate = 2 V/ns
RQ =
250Ω
(b)
Note
22. Unless otherwise noted, test conditions assume signal transition time of 2V/ns, timing reference levels of 0.75V, Vref = 0.75V, RQ = 250Ω, VDDQ = 1.5V, input pulse
levels of 0.25V to 1.25V, and output loading of the specified IOL/IOH and load capacitance shown in (a) of “AC Test Loads and Waveforms” on page 21.
Document Number: 001-05389 Rev. *E
Page 21 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Switching Characteristics
Over the Operating Range [22, 23]
CY
Consortium
Parameter Parameter
Description
VDD(Typical) to the First Access[24]
tPOWER
tCYC
tKHKH
K Clock Cycle Time
375 MHz
333 MHz
300 MHz
Min Max Min Max Min Max
1
1
2.66 8.40
3.0
1
8.40
Unit
ms
3.3
8.40
ns
tKH
tKHKL
Input Clock (K/K) HIGH
0.4
–
0.4
0.4
–
tCYC
tKL
tKLKH
Input Clock (K/K) LOW
0.4
–
0.4
0.4
–
tCYC
tKHKH
tKHKH
K Clock Rise to K Clock Rise (rising edge to rising edge)
1.13
–
1.28
1.40
–
ns
–
Setup Times
tSA
tAVKH
Address Setup to K Clock Rise
0.4
–
0.4
–
0.4
–
ns
tSC
tIVKH
Control Setup to K Clock Rise (RPS, WPS)
0.4
–
0.4
–
0.4
–
ns
tSCDDR
tIVKH
Double Data Rate Control Setup to Clock (K/K) Rise
(BWS0, BWS1, BWS2, BWS3)
0.28
–
0.28
–
0.28
–
ns
tSD
tDVKH
D[X:0] Setup to Clock (K/K) Rise
0.28
–
0.28
–
0.28
–
ns
Hold Times
tHA
tKHAX
Address Hold after K Clock Rise
0.4
–
0.4
–
0.4
–
ns
tHC
tKHIX
Control Hold after K Clock Rise (RPS, WPS)
0.4
–
0.4
–
0.4
–
ns
tHCDDR
tKHIX
Double Data Rate Control Hold after Clock (K/K) Rise
(BWS0, BWS1, BWS2, BWS3)
0.28
–
0.28
–
0.28
–
ns
tHD
tKHDX
D[X:0] Hold after Clock (K/K) Rise
0.28
–
0.28
–
0.28
–
ns
–
0.45
–
0.45
–
0.45
ns
–0.45
–
–0.45
–
–0.45
–
ns
–
0.45
–
0.45
–
0.45
ns
–0.45
–
–0.45
–
–0.45
–
ns
Output Times
tCO
tCHQV
K/K Clock Rise to Data Valid
tDOH
tCHQX
Data Output Hold after Output K/K Clock Rise
(Active to Active)
tCCQO
tCHCQV
K/K Clock Rise to Echo Clock Valid
tCQOH
tCHCQX
Echo Clock Hold after K/K Clock Rise
tCQD
tCQHQV
Echo Clock High to Data Valid
0.2
ns
tCQDOH
tCQHQX
Echo Clock High to Data Invalid
–0.2
–
–0.2
–
–0.2
–
ns
tCQH
tCQHCQL
Output Clock (CQ/CQ) HIGH[27]
0.88
–
1.03
–
1.15
–
ns
0.88
–
1.03
–
1.15
–
ns
ns
Rise[27]
0.2
0.2
tCQHCQH
tCQHCQH
CQ Clock Rise to CQ Clock
(rising edge to rising edge)
tCHZ
tCHQZ
Clock (K/K) Rise to High-Z (Active to High-Z)[25, 26]
–
0.45
–
0.45
–
0.45
tCLZ
tCHQX1
Clock (K/K) Rise to
Low-Z[25, 26]
–0.45
–
–0.45
–
–0.45
–
tQVLD
tCQHQVLD
Echo Clock High to QVLD Valid[28]
–0.20 0.20 –0.20 0.20 –0.20 0.20
ns
ns
Notes
23. When a part with a maximum frequency above 300MHz is operating at a lower clock frequency, it requires the input timings of the frequency range in which it is being
operated and outputs data with the output timings of that frequency range.
24. This part has a voltage regulator internally; tPOWER is the time that the power needs to be supplied above VDD minimum initially before a read or write operation can
be initiated.Hold to >VIH or <VIL.
25. tCHZ, tCLZ, are specified with a load capacitance of 5 pF as in part (b) of AC Test Loads. Transition is measured ± 100 mV from steady-state voltage.
26. At any given voltage and temperature tCHZ is less than tCLZ and tCHZ less than tCO.
27. These parameters are extrapolated from the input timing parameters (tKHKH-250ps, where 250ps is the internal jitter. An input jitter of 200ps(tKCVAR) is already included
in the tKHKH). These parameters are only guaranteed by design and are not tested in production.
28. tQVLD spec is applicable for both rising and falling edges of QVLD signal.
Document Number: 001-05389 Rev. *E
Page 22 of 28
CY7C1541V18
CY7C1556V18
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CY7C1545V18
Switching Characteristics
Over the Operating Range [22, 23] (continued)
CY
Consortium
Parameter Parameter
Description
375 MHz
333 MHz
300 MHz
Min Max Min Max Min Max
Unit
DLL Timing
tKC Var
tKC Var
Clock Phase Jitter
–
0.20
–
0.20
–
0.20
ns
tKC lock
tKC lock
DLL Lock Time (K)
2048
–
2048
–
2048
–
Cycles
tKC Reset
tKC Reset
K Static to DLL Reset[29]
30
30
30
ns
Note
29. Hold to >VIH or <VIL.
Document Number: 001-05389 Rev. *E
Page 23 of 28
CY7C1541V18
CY7C1556V18
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CY7C1545V18
Switching Waveforms
Read/Write/Deselect Sequence [30, 31, 32]
Figure 3. Waveform for 2.0 Cycle Read Latency
NOP
1
READ
2
WRITE
3
READ
4
NOP
6
WRITE
5
7
8
K
t KH
t CYC
t KL
t KHKH
K
RPS
t SC
tHC
t SC
t HC
WPS
A
A0
A1
A3
A2
t HD
t SA t HA
t SD
D
t HD
t SD
D10
D11
D12
D13
D30
D31
D32
D33
t QVLD
t QVLD
QVLD
t CLZ
Q
tDOH
t
CO
Q00
(Read Latency = 2.0 Cycles)
tCQDOH
tCQD
Q01
Q02
Q03
Q20
Q21
Q22
tCHZ
Q23
tCCQO
tCQOH
CQ
t CQH
t CQHCQH
tCQOH
t CCQO
CQ
DON’T CARE
UNDEFINED
Notes
30. Q00 refers to output from address A0. Q01 refers to output from the next internal burst address following A0, i.e, A0+1.
31. Outputs are disabled (High-Z) one clock cycle after a NOP.
32. In this example, if address A2 = A1,then data Q20 = D10 and Q21 = D11. Write data is forwarded immediately as read results. This note applies to the whole diagram.
Document Number: 001-05389 Rev. *E
Page 24 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Ordering Information
Not all of the speed, package and temperature ranges are available. Please contact your local sales representative or
visit www.cypress.com for actual products offered.
Speed
(MHz)
375
Ordering Code
CY7C1541V18-375BZC
Package
Diagram
Package Type
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm)
Operating
Range
Commercial
CY7C1556V18-375BZC
CY7C1543V18-375BZC
CY7C1545V18-375BZC
CY7C1541V18-375BZXC
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm) Pb-Free
CY7C1556V18-375BZXC
CY7C1543V18-375BZXC
CY7C1545V18-375BZXC
CY7C1541V18-375BZI
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm)
Industrial
CY7C1556V18-375BZI
CY7C1543V18-375BZI
CY7C1545V18-375BZI
CY7C1541V18-375BZXI
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm) Pb-Free
CY7C1556V18-375BZXI
CY7C1543V18-375BZXI
CY7C1545V18-375BZXI
333
CY7C1541V18-333BZC
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm)
Commercial
CY7C1556V18-333BZC
CY7C1543V18-333BZC
CY7C1545V18-333BZC
CY7C1541V18-333BZXC
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm) Pb-Free
CY7C1556V18-333BZXC
CY7C1543V18-333BZXC
CY7C1545V18-333BZXC
CY7C1541V18-333BZI
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm)
Industrial
CY7C1556V18-333BZI
CY7C1543V18-333BZI
CY7C1545V18-333BZI
CY7C1541V18-333BZXI
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm) Pb-Free
CY7C1556V18-333BZXI
CY7C1543V18-333BZXI
CY7C1545V18-333BZXI
Document Number: 001-05389 Rev. *E
Page 25 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Ordering Information
(continued)
Not all of the speed, package and temperature ranges are available. Please contact your local sales representative or
visit www.cypress.com for actual products offered.
Speed
(MHz)
300
Ordering Code
CY7C1541V18-300BZC
Package
Diagram
Package Type
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm)
Operating
Range
Commercial
CY7C1556V18-300BZC
CY7C1543V18-300BZC
CY7C1545V18-300BZC
CY7C1541V18-300BZXC
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm) Pb-Free
CY7C1556V18-300BZXC
CY7C1543V18-300BZXC
CY7C1545V18-300BZXC
CY7C1541V18-300BZI
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm)
Industrial
CY7C1556V18-300BZI
CY7C1543V18-300BZI
CY7C1545V18-300BZI
CY7C1541V18-300BZXI
51-85195 165-Ball Fine Pitch Ball Grid Array (15 x 17 x 1.4 mm) Pb-Free
CY7C1556V18-300BZXI
CY7C1543V18-300BZXI
CY7C1545V18-300BZXI
Document Number: 001-05389 Rev. *E
Page 26 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Package Diagram
Figure 4. 165-ball FBGA (15 x 17 x 1.40 mm), 51-85195
"/44/- 6)%7
4/0 6)%7
Œ - # ! "
Œ
0). #/2.%2
Œ - #
0). #/2.%2
8
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"
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#
#
!
$
$
&
&
'
'
(
*
%
¼
%
(
*
+
,
,
+
-
-
.
.
0
0
2
2
!
"
¼
#
¼
¼
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Document Number: 001-05389 Rev. *E
Page 27 of 28
CY7C1541V18
CY7C1556V18
CY7C1543V18
CY7C1545V18
Document History Page
Document Title: CY7C1541V18/CY7C1556V18/CY7C1543V18/CY7C1545V18, 72-Mbit QDR™-II+ SRAM 4-Word Burst Architecture (2.0 Cycle Read Latency)
Document Number: 001-05389
REV.
ECN NO.
ISSUE
DATE
ORIG. OF
CHANGE
**
403090
See ECN
VEE
New Data Sheet
*A
425252
See ECN
VEE
Updated the DLL Section
Fixed typos in the DC and AC parameter section
Updated the switching waveform
Updated the Power up sequence
Added additional parameters in the AC timing
*B
437000
See ECN
IGS
ECN for Show on web
*C
461934
See ECN
NXR
Moved the Selection Guide table from page# 3 to page# 1
Modified Application Diagram
Changed tTH and tTL from 40 ns to 20 ns, changed tTMSS, tTDIS, tCS, tTMSH, tTDIH, tCH
from 10 ns to 5 ns and changed tTDOV from 20 ns to 10 ns in TAP AC Switching
Characteristics table
Modified Power Up waveform
Included Maximum ratings for Supply Voltage on VDDQ Relative to GND
Changed the Maximum Ratings for DC Input Voltage from VDDQ to VDD
Changed the Pin Definition of IX from Input Load current to Input Leakage current on
page#18
*D
497567
See ECN
NXR
Changed the VDDQ operating voltage to 1.4V to VDD in the Features section, in
Operating Range table and in the DC Electrical Characteristics table
Added foot note in page# 1
Changed the Maximum rating of Ambient Temperature with Power Applied from –10°C
to +85°C to –55°C to +125°C
Changed VREF (Max) spec from 0.85V to 0.95V in the DC Electrical Characteristics
table and in the note below the table
Updated footnote #21 to specify Overshoot and Undershoot Spec
Updated IDD and ISB values
Updated ΘJA and ΘJC values
Removed x9 part and its related information
Updated footnote #25
*E
1351243 See ECN
VKN/FSU
DESCRIPTION OF CHANGE
Converted from preliminary to final
Added x8 and x9 parts
Changed tCYC max spec to 8.4 ns for all speed bins
Updated footnote# 23
Updated Ordering Information table
© Cypress Semiconductor Corporation, 2005-2007. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use
of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used
for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use
as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support
systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and foreign),
United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of,
and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in conjunction with a Cypress
integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as specified above is prohibited without
the express written permission of Cypress.
Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not
assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where
a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer
assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
Document Number: 001-05389 Rev. *E
Revised July 24, 2007
Page 28 of 28
QDR RAMs and Quad Data Rate RAMs comprise a new family of products developed by Cypress, IDT, NEC, Renesas, and Samsung. All product and company names mentioned in this document
are the trademarks of their respective holders.
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