Cypress CY7C1526JV18, CY7C1513JV18, CY7C1515JV18, CY7C1511JV18 User Manual

72-Mbit QDR™-II SRAM 4-Word
Burst Architecture
CY7C1511JV18, CY7C1526JV18
CY7C1513JV18, CY7C1515JV18

Features

Configurations

300 MHz clock for high bandwidth
4-word burst for reducing address bus frequency
Double Data Rate (DDR) interfaces on both read and write ports
(data transferred at 600 MHz) at 300 MHz
Two input clocks (K and K) for precise DDR timingSRAM uses rising edges only
Two input clocks for output data (C and C) to minimize clock
skew and flight time mismatches
Echo clocks (CQ and CQ) simplify data capture in high-speed
systems
Single multiplexed address input bus latches address inputs
for read and write ports
Separate port selects for depth expansion
Synchronous internally self-timed writes
QDR-II operates with 1.5 cycle read latency when the Delay
Lock Loop (DLL) is enabled
Operates like a QDR-I device with 1 cycle read latency in DLL
off mode
Available in x8, x9, x18, and x36 configurations
Full data coherency, providing most current data
Core V
Available in 165-Ball FBGA package (15 x 17 x 1.4 mm)
Offered in both Pb-free and non Pb-free packages
Variable drive HSTL output buffers
JTAG 1149.1 compatible test access port
Delay Lock Loop (DLL) for accurate data placement
= 1.8 (± 0.1V); IO V
DD
= 1.4V to V
DDQ
DD
CY7C1511JV18 – 8M x 8 CY7C1526JV18 – 8M x 9 CY7C1513JV18 – 4M x 18 CY7C1515JV18 – 2M x 36

Functional Description

The CY7C1511JV18, CY7C1526JV18, CY7C1513JV18, and CY7C1515JV18 are 1.8V Synchronous Pipelined SRAMs, equipped with QDR-II architecture. QDR-II architecture consists of two separate ports: the read port and the write port 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 that exists with common IO devices. Each port can be accessed 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. T o maximize dat a throughput, both read and write ports are equipped with DDR interfaces. Each addre ss location is associated with four 8-bit words (CY7C1511JV18), 9-bit words (CY7C1526JV18), 18-bit words (CY7C1513JV18), or 36-bit words (CY7C1515JV18) that burst sequentially into or out of the device. Because 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
and C system design by eliminating bus “turn-arounds”.
Depth expansion is accomplished with port selects, which enables each port to operate independently.
All synchronous inputs pass through input registers controlled by the K or K registers controlled by the C or C
input clocks. All data outputs pass through output
(or K or K in a single clock domain) input clocks. Writes are conducted with on-chip synchronous self-timed write circuitry.
and C

Selection Guide

Description 300 MHz Unit
Maximum Operating Frequency 300 MHz Maximum Operating Current x8 1090 mA
x9 1090 x18 1115 x36 1140
Cypress Semiconductor Corporation 198 Champion Court San Jose, CA 95134-1709 408-943-2600 Document Number: 001-12560 Rev. *C Revised March 10, 2008
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CY7C1511JV18, CY7C1526JV18
CY7C1513JV18, CY7C1515JV18

Logic Block Diagram (CY7C1511JV18)

2M x 8 Array
CLK
A
(20:0)
Gen.
K
K
Control
Logic
Address Register
D
[7:0]
Read Add. Decode
Read Data Reg.
RPS
WPS
Control
Logic
Address Register
Reg.
Reg.
Reg.
16
21
32
8
NWS
[1:0]
V
REF
Write Add. Decode
Write
Reg
16
A
(20:0)
21
8
CQ
CQ
DOFF
Q
[7:0]
8
8
8
8
Write
Reg
Write
Reg
Write
Reg
C
C
2M x 8 Array
2M x 8 Array
2M x 8 Array
CLK
A
(20:0)
Gen.
K
K
Control
Logic
Address Register
D
[8:0]
Read Add. Decode
Read Data Reg.
RPS
WPS
Control
Logic
Address Register
Reg.
Reg.
Reg.
18
21
36
9
BWS
[0]
V
REF
Write Add. Decode
Write
Reg
18
A
(20:0)
21
9
CQ
CQ
DOFF
Q
[8:0]
9
9
9
9
Write
Reg
Write
Reg
Write
Reg
C
C
2M x 9 Array
2M x 9 Array
2M x 9 Array
2M x 9 Array

Logic Block Diagram (CY7C1526JV18)

Document Number: 001-12560 Rev. *C Page 2 of 27
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CY7C1511JV18, CY7C1526JV18
CY7C1513JV18, CY7C1515JV18

Logic Block Diagram (CY7C1513JV18)

CLK
A
(19:0)
Gen.
K
K
Control
Logic
Address Register
D
[17:0]
Read Add. Decode
Read Data Reg.
RPS
WPS
Control
Logic
Address Register
Reg.
Reg.
Reg.
36
20
72
18
BWS
[1:0]
V
REF
Write Add. Decode
Write
Reg
36
A
(19:0)
20
18
CQ
CQ
DOFF
Q
[17:0]
18
18
18
18
Write
Reg
Write
Reg
Write
Reg
C
C
1M x 18 Array
1M x 18 Array
1M x 18 Array
1M x 18 Array
512K x 36 Array
CLK
A
(18:0)
Gen.
K
K
Control
Logic
Address Register
D
[35:0]
Read Add. Decode
Read Data Reg.
RPS
WPS
Control
Logic
Address Register
Reg.
Reg.
Reg.
72
19
144
36
BWS
[3:0]
V
REF
Write Add. Decode
Write
Reg
72
A
(18:0)
19
512K x 36 Array
512K x 36 Array
512K x 36 Array
36
CQ
CQ
DOFF
Q
[35:0]
36
36
36
36
Write
Reg
Write
Reg
Write
Reg
C
C

Logic Block Diagram (CY7C1515JV18)

Document Number: 001-12560 Rev. *C Page 3 of 27
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CY7C1511JV18, CY7C1526JV18
CY7C1513JV18, CY7C1515JV18

Pin Configuration

Note
1. NC/144M and NC/288M are not connected to the die and can be tied to any voltage level.
The pin configuration for CY7C1511JV18, CY7C1513JV18, and CY7C1515JV18 follow.

165-Ball FBGA (15 x 17 x 1.4 mm) Pinout

CY7C1511JV18 (8M x 8)
1234567891011
A CQ
AAWPSNWS
1
B NC NC NC A NC/288M K NWS C NC NC NC V D NC D4 NC V E NC NC Q4 V F NC NC NC V
G NC D5 Q5 V
H DOFF
V
REF
V
DDQ
V
J NC NC NC V K NC NC NC V L NC Q6 D6 V
M NC NC NC V
N NC D7 NC V
SS
SS DDQ DDQ DDQ DDQ DDQ DDQ DDQ
SS
SS
ANCAVSSNC NC D3
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
AAAVSSNC NC NC
P NC NC Q7 A A C A A NC NC NC R TDO TCK A A A C
K NC/144M RPS AACQ
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V V V V V V V V V
[1]
0
SS SS DD DD DD DD DD SS SS
ANCNCQ3
V V V V V V V
V
DDQ DDQ DDQ DDQ DDQ DDQ DDQ
V
SS
SS
NC NC NC NC D2 Q2 NC NC NC NC NC NC
V
DDQ
V
REF
NC Q1 D1 NC NC NC NC NC Q0 NC NC D0
AAATMSTDI
ZQ
CY7C1526JV18 (8M x 9)
1234567891011
A CQ B NC NC NC A NC/288M K BWS C NC NC NC V D NC D5 NC V E NC NC Q5 V F NC NC NC V
G NC D6 Q6 V
H DOFF
J NC NC NC V K NC NC NC V L NC Q7 D7 V
M NC NC NC V
N NC D8 NC V
AAWPSNC K NC/144M RPS AACQ
ANCNCQ4
V V V V V V V
V
DDQ DDQ DDQ DDQ DDQ DDQ DDQ
V
SS
SS
NC NC NC NC D3 Q3 NC NC NC NC NC NC
V
DDQ
V
REF
NC Q2 D2 NC NC NC NC NC Q1 NC NC D1
ZQ
V
REF
V
DDQ
V
SS
SS DDQ DDQ DDQ DDQ DDQ DDQ DDQ
SS
SS
0
ANCAVSSNC NC D4
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
AAAVSSNC NC NC
P NC NC Q8 A A C A A NC D0 Q0 R TDO TCK A A A C
AAATMSTDI
Document Number: 001-12560 Rev. *C Page 4 of 27
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CY7C1511JV18, CY7C1526JV18
CY7C1513JV18, CY7C1515JV18
Pin Configuration
The pin configuration for CY7C1511JV18, CY7C1513JV18, and CY7C1515JV18 follow.
165-Ball FBGA (15 x 17 x 1.4 mm) Pinout
CY7C1513JV18 (4M x 18)
1234567891011
A CQ
NC/144M A WPS BWS
1
B NC Q9 D9 A NC K BWS C NC NC D10 V D NC D11 Q10 V E NC NC Q11 V F NC Q12 D12 V
G NC D13 Q13 V
H DOFF
V
REF
V
DDQ
V
J NC NC D14 V K NC NC Q14 V L NC Q15 D15 V
M NC NC D16 V
N NC D17 Q16 V
SS
SS DDQ DDQ DDQ DDQ DDQ DDQ DDQ
SS
SS
ANCAVSSNC Q7 D8
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
AAAVSSNC NC D1
P NC NC Q17 A A C A A NC D0 Q0 R TDO TCK A A A C
K NC/288M RPS AACQ
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V V V V V V V V V
[1]
(continued)
0
SS SS DD DD DD DD DD SS SS
ANCNCQ8
V V V V V V V
V
DDQ DDQ DDQ DDQ DDQ DDQ DDQ
V
SS
SS
NC NC D7 NC D6 Q6 NC NC Q5 NC NC D5
V
DDQ
V
REF
NC Q4 D4 NC D3 Q3 NC NC Q2 NC Q1 D2
AAATMSTDI
ZQ
CY7C1515JV18 (2M x 36)
1234567891011
A CQ
NC/288M A WPS BWS
B Q27 Q18 D18 A BWS C D27 Q28 D19 V D D28 D20 Q19 V E Q29 D29 Q20 V F Q30 Q21 D21 V
G D30 D22 Q22 V
H DOFF
V
REF
V
DDQ
V
J D31 Q31 D23 V K Q32 D32 Q23 V L Q33 Q24 D24 V
M D33 Q34 D25 V
N D34 D26 Q25 V
SS
SS DDQ DDQ DDQ DDQ DDQ DDQ DDQ
SS
SS
ANCAVSSD16 Q7 D8
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
AAAVSSQ10 D9 D1
2 3
K BWS
RPS A NC/144M CQ
1
KBWS0AD17Q17Q8
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
SS
V
DD
V
DD
V
DD
V
DD
V
DD
V
SS
V
SS
V V V V V V V
V
DDQ DDQ DDQ DDQ DDQ DDQ DDQ
V
SS
SS
Q16 D15 D7 Q15 D6 Q6 D14 Q14 Q5 Q13 D13 D5
V
DDQ
V
REF
D12 Q4 D4 Q12 D3 Q3 D11 Q11 Q2 D10 Q1 D2
ZQ
P Q35 D35 Q26 A A C A A Q9 D0 Q0 R TDO TCK A A A C
AAATMSTDI
Document Number: 001-12560 Rev. *C Page 5 of 27
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CY7C1513JV18, CY7C1515JV18

Pin Definitions

Pin Name IO Pin Description
D
[x:0]
WPS Input-
NWS
,
0
NWS
,
1
BWS0,
,
BWS
1
BWS
,
2
BWS
3
A Input-
Q
[x:0]
RPS Input-
C Input Clock Positive Input Clock for Output Data. C is used in conjunction with C
C
K Input Clock Positive Input Clock In put. The rising edge of K is used to capture synchronous inputs to the device
K
Input-
Synchronous
Data Input Signals. Sampled on the rising edge of K and K clocks when valid write operations are active. CY7C1511JV18 D CY7C1526JV18 D CY7C1513JV18 D CY7C1515JV18 D
[7:0] [8:0] [17:0] [35:0]
Write Port Select Active LOW. Sampled on the rising edge of the K clock. When asserted active, a
Synchronous
Input-
Synchronous
Input-
Synchronous
write operation is initiated. Deasserting deselects the write port. Deselecting the write port ignores D Nibble Write Select 0, 1 Active LOW (CY7C1511JV18 Only). Sampled on the rising edge of the K
and K
clocks
when write operations are active the current portion of the write operations. All the Nibble Write Selects are sampled on the same edge as the data. Deselecting a Nibble Write Select ignores the corresponding nibble of data and it is not written into the device
. Used to select which nibble is written into the device
NWS
controls D
0
and NWS1 controls D
[3:0]
[7:4]
.
.
during
Byte Write Select 0, 1, 2, and 3 Active LOW . Sampled on the rising edge of the K and K clocks when write operations are active. Used to select which byte is written into the device during the current portion of the write operations. Bytes not written remain unaltered. CY7C1526JV18 BWS CY7C1513JV18 BWS0 controls D CY7C1515JV18 BWS0 controls D BWS
controls D
2
All the Byte Write Selects are sampled on the same edge as the data. Deselecting a Byte Write Select
[26:18]
ignores the corresponding byte of data and it is not written into the device
controls D
0
and BWS3 controls D
[8:0]
and BWS1 controls D
[8:0]
, BWS1 controls D
[8:0]
[35:27].
[17:9]
[17:9].
,
.
Address Inputs. Sampled on the rising edge of the K clock during active read and write operations. These
Synchronous
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 CY7C1511JV18, 8M x 9 (4 arrays each of 2M x 9) for CY7C1526JV18, 4M x 18 (4 arrays each of 1M x 18) for CY7C1513JV18 and 2M x 36 (4 arrays each of 512K x 36) for CY7C1515JV18. Therefore, only 21 address inputs are needed to access the entire memory array of CY7C1511JV18 and CY7C1526JV18, 20 address inputs for CY7C1513JV18 and 19 address inputs for CY7C1515JV18. These inputs are ignored when the appropriate port is deselected.
Outputs-
Synchronous
Data Output Signals. These pins drive out the requested data when the read operation is active. Valid data is driven out on the rising edge of the C and C single clock mode. On deselecting the read port, Q CY7C1511JV18 Q CY7C1526JV18 Q CY7C1513JV18 Q CY7C1515JV18 Q
[7:0] [8:0] [17:0] [35:0]
clocks during read operations, or K and K when in
are automatically tri-stated.
[x:0]
Read Port Select Active LOW . Sampled on the rising edge of positive input clock (K). When active, a
Synchronous
read operation is initiated. Deasserting deselects the read port. When deselected, the pending access is allowed to complete and the output drivers are automatically tri-stated following the next rising edge of the C clock. Each read access consists of a burst of four sequential transfers.
to clock out the read data from
the device. C and C
can be used together to deskew the flight times of various devices on the board back
to the controller. See Application Example on page 10 for further details.
Input Clock Negative Input Clock for Output Data. C is used in conjunction with C to clock out the read data from
the device. C and C
can be used together to deskew the flight times of various devices on the board back
to the controller. See Application Example on page 10 for further details.
and to drive out data through Q edge of K.
when in single clock mode. All accesses are initiated on the rising
[x:0]
Input Clock Negative Input Clock Input. K is used to capture synchronous inputs being presented to the device and
to drive out data through Q
when in single clock mode.
[x:0]
[x:0]
.
Document Number: 001-12560 Rev. *C Page 6 of 27
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CY7C1513JV18, CY7C1515JV18
Pin Definitions (continued)
Pin Name IO Pin Description
CQ Echo Clock CQ is Referenced with Respect to C. This is a free running clock and is synchronized to the input clock
for output data (C) of the QDR-II. In the single clock mode, CQ is generated with respect to K. The timings for the echo clocks are shown in the Switching Characteristics on page 23.
CQ
ZQ Input Output Impedance Matching Input. This input is used to tune the device outputs to the system data bus
DOFF
TDO Output TDO for JTAG. 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.
V
REF
V
DD
V
SS
V
DDQ
Echo Clock CQ is Referenced with Respect to C. This is a free running clock and is synchronized to the input clock
Input DLL Turn Off Active LOW . Connecting this pin to ground turns off the DLL inside the device. The
Input-
Reference
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.
for output data (C for the echo clocks are shown in the Switching Characteristics on page 23.
impedance. CQ, CQ, and Q between ZQ and ground. Alternatively, this pin can be connected directly to V minimum impedance mode. This pin cannot be connected directly to GND or left unconnected.
timings in the DLL turned off operation differs 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.
Reference Voltage Input. Static input used to set the reference level for HSTL inputs, outputs, and AC measurement points.
) of the QDR-II. In the single clock mode, CQ is generated with respect to K. The timings
output impedance are set to 0.2 x RQ, where RQ is a resistor connected
[x:0]
, which enables the
DDQ
Document Number: 001-12560 Rev. *C Page 7 of 27
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CY7C1513JV18, CY7C1515JV18

Functional Overview

The CY7C1511JV18, CY7C1526JV18, CY7C1513JV18, CY7C1515JV18 are synchronous pipelined Burst SRAMs with 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 flows out through the read port. These devices multiplex the address inputs 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 CY7C1511JV18, four 9-bit data transfers in the case of CY7C1526JV18, four 18-bit data transfers in the case of CY7C1513JV18, and four 36-bit data transfers in the case of CY7C1515JV18 in two clock cycles.
This device operates with a read latency of one and half cycles when DOFF connected to VSS then device behaves in QDR-I mode with a read latency of one clock cycle.
Accesses for both ports are initiated on the positive input clock (K). All synchronous input timing is referenced from the rising edge of the input clocks (K and K enced to the output clocks (C and C clock mode).
All synchronous data inputs (D controlled by the input clocks (K and K). All synchronous data outputs (Q rising edge of the output clocks (C and C, or K and K when in single clock mode).
All synchronous control (RPS through input registers controlled by the rising edge of the input clocks (K and K
CY7C1513JV18 is described in the following sections. The same basic descriptions apply to CY7C1511JV18, CY7C1526JV18 and CY7C1515JV18.

Read Operations

The CY7C1513JV18 is organized internally as four 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 the address inputs is stored in the read address register. Following the next K clock rise, the corre­sponding lowest order 18-bit word of data is driven onto the Q
[17:0]
quent rising edge of C, the next 18-bit data word is driven onto the Q have been driven out onto Q
0.45 ns from the rising edge of the output clock (C or C when in single clock mode). T o maintain the internal logic, each
K read access must be allowed to complete. Each read access consists of four 18-bit data words and takes two clock cycles to complete. Therefore, read accesses to the device can not be
pin is tied HIGH. When DOFF pin is set LOW or
) and all output timing is refer-
, or K and K when in single
) pass through input registers
[x:0]
) pass through output registers controlled by the
[x:0]
, WPS, BWS
) inputs pass
[x:0]
).
using C as the output timing reference. On the subse-
. This process continues until all four 18-bit data words
[17:0]
. The requested data is valid
[17:0]
, or K or
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 output clocks (C and C
, or K and K when in
single clock mode). When the read port is deselected, the CY7C1513JV18 first
completes the pending read transactions. Synchronous internal circuitry automatically tri-states the outputs following the next rising edge of the positive output clock (C). This enables 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 the lower 18-bit write data register, provided BWS
is latched and stored into
[17:0]
[1:0]
are both asserted active. On the subsequent rising edge of the negative input clock (K
) the information presented to D
into the write data register, provided BWS
[1:0]
is also stored
[17:0]
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 CY7C1513JV18. A write operation is initiated as described in the Write Operations section. The bytes that are written are determined by BWS
and
0
BWS1, which are sampled with each set of 18-bit data words. Asserting the byte write select input during the data portion of a write latches the data being presented and writes it into the device. Deasserting the byte write select input during the data portion of a write enables the data stored in the device for that byte to remain unaltered. This feature can be used to simplify read, modify, or write operations to a byte write operation.

Single Clock Mode

The CY7C1511JV18 can be used with a single clock that controls both the input and output registers. In this mode the device recognizes only a single pair of input clocks (K and K both the input and output registers. This operation is identical to the operation if the device had zero skew between the K/K C/C
clocks. All timing parameters remain the same in this mode. To use this mode of operation, the user must tie C and C at power on. This function is a strap option and not alterable during device operation.
) that control
and
HIGH
Document Number: 001-12560 Rev. *C Page 8 of 27
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CY7C1513JV18, CY7C1515JV18

Concurrent Transactions

The read and write ports on the CY7C1513JV18 operates completely independently of one another. As 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.
Read access and write access must be scheduled such that one transaction is initiated on any clock cycle. If both ports are selected on the same K clock rise, the arbitration depends on the previous state of the SRAM. If both ports are deselected, the read port takes priority. If a read was initiated on the previous cycle, the write port takes priority (as read operations can not be initiated on consecutive cycles). If a write was initiated on the previous cycle, the read port takes priority (as write operations can not be initiated on consecutive cycles). Therefore, asserting both port selects active from a deselected state results in alter­nating read or write operations being initiated, with the first access being a read.

Depth Expansion

The CY7C1513JV18 has a port select input for each port. This enables 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 before the device is deselected.

Programmable Impedance

An external resistor, RQ, must be connected between the ZQ pin on the SRAM and V 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 output impedance is adjusted every 1024 cycles upon power up to account for drifts in supply voltage and temperature.
to allow the SRAM to adjust its output
SS
, with V
=1.5V. The
DDQ

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 C and CQ with respect to C. These are free-running clocks and are synchronized to the output clock of the QDR-II. In the single clock mode, CQ is generated with respect to K and CQ with respect to K. The timing for the echo clocks is shown in the
Switching Characteristics on page 23.
is referenced
is generated
DLL
These chips utilize a DLL that is designed to function between 120 MHz and the specified maximum clock frequency. During power up, when the DOFF is tied HIGH, the DLL is locked after 1024 cycles of stable clock. The DLL can also be reset by slowing or stopping the input clocks K and K ns. However, it is not necessary to reset the DLL to lock to the desired frequency. The DLL automatically locks 1024 clock cycles after a stable clock is presented. The DLL may be disabled by applying ground to the DOFF pin. When the DLL is turned off, the device behaves in QDR-I mode (with one cycle latency and a longer access time). For information refer to the application note DLL Considerations in QDRII/DDRII.
for a minimum of 30
Document Number: 001-12560 Rev. *C Page 9 of 27
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