CY7C1241KV18 Datasheet, PDF (1/28 Pages) Cypress Semiconductor – 36-Mbit QDR® II+ SRAM 4-Word Burst Architecture (2.0 Cycle Read Latency)

CY7C1241KV18, CY7C1256KV18
CY7C1243KV18, CY7C1245KV18
36-Mbit QDR^® II+ SRAM 4-Word Burst
Architecture (2.0 Cycle Read Latency)
36-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
■ 450 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 900 MHz) at 450 MHz
■ 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 read and write ports
■ Separate port selects for depth expansion
■ Synchronous internally self-timed writes
■ QDR^® II+ operates with 2.0 cycle read latency when DOFF is
asserted HIGH
■ Operates similar to QDR I device with 1 cycle read latency when
DOFF is asserted LOW
■ Available in × 8, × 9, × 18, and × 36 configurations
■ Full data coherency, providing most current data
■ Core V_DD = 1.8 V ± 0.1 V; I/O V_DDQ = 1.4 V to V_DD[1]
❐ Supports both 1.5 V and 1.8 V I/O supply
■ HSTL inputs and variable drive HSTL output buffers
■ Available in 165-ball FBGA package (13 × 15 × 1.4 mm)
■ Offered in both Pb-free and non Pb-free packages
■ JTAG 1149.1 compatible test access port
■ Phase-locked loop (PLL) for accurate data placement
With Read Cycle Latency of 2.0 cycles:
CY7C1241KV18 – 4 M × 8
CY7C1256KV18 – 4 M × 9
CY7C1243KV18 – 2 M × 18
CY7C1245KV18 – 1 M × 36
Functional Description
The CY7C1241KV18, CY7C1256KV18, CY7C1243KV18, and
CY7C1245KV18 are 1.8 V synchronous pipelined SRAMs,
equipped with QDR II+ architecture. Similar to 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 “turnaround” the
data bus that exists with common I/O devices. Each port is
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. To maximize data
throughput, both read and write ports are equipped with DDR
interfaces. Each address location is associated with four 8-bit
words (CY7C1241KV18), 9-bit words (CY7C1256KV18), 18-bit
words (CY7C1243KV18), or 36-bit words (CY7C1245KV18) that
burst sequentially into or out of the device. Because data is
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 “turnarounds”.
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 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.
Table 1. Selection Guide
Description
450 MHz
400 MHz
375 MHz
333 MHz
Unit
Maximum operating frequency
Maximum operating current
450
400
375
333
MHz
×8
710
650
620
560
mA
×9
710
650
620
560
× 18
720
660
630
570
× 36
1020
920
870
790
Note
1. The Cypress QDR II+ devices surpass the QDR consortium specification and can support V_DDQ = 1.4 V to V_DD.
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 001-57832 Rev. *B
• San Jose, CA 95134-1709 • 408-943-2600
Revised February 24, 2011
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