72-Mbit (2M x 36/4M x 18/1M x 72)
Flow-Through SRAM with NoBL™ Architecture
CY7C1471V25
CY7C1473V25
CY7C1475V25
Cypress Semiconductor Corporation
•
198 Champion Court
•
San Jose
,
CA 95134-1709
•
408-943-2600
Document #: 38-05287 Rev. *I
Revised July 04, 2007
Features
• No Bus Latency™ (NoBL™) architecture eliminates dead
cycles between write and read cycles
• Supports up to 133 MHz bus operations with zero wait states
• Data is transferred on every clock
• Pin compatible and functionally equivalent to ZBT™ devices
• Internally self timed output buffer control to eliminate the
need to use OE
• Registered inputs for flow through operation
• Byte Write capability
• 2.5V/1.8V IO supply (V
DDQ
)
• Fast clock-to-output times
— 6.5 ns (for 133-MHz device)
• Clock Enable (CEN) pin to enable clock and suspend
operation
• Synchronous self timed writes
• Asynchronous Output Enable (OE)
• CY7C1471V25, CY7C1473V25 available in
JEDEC-standard Pb-free 100-pin TQFP, Pb-free and
non-Pb-free 165-Ball FBGA package. CY7C1475V25
available in Pb-free and non-Pb-free 209-Ball FBGA
package.
• Three Chip Enables (CE
1
, CE
2
, CE
3
) for simple depth
expansion.
• Automatic power down feature available using ZZ mode or
CE deselect.
• IEEE 1149.1 JTAG Boundary Scan compatible
• Burst Capability - linear or interleaved burst order
• Low standby power
Functional Description
[1]
The CY7C1471V25, CY7C1473V25, and CY7C1475V25 are
2.5V, 2M x 36/4M x 18/1M x 72 synchronous flow through burst
SRAMs designed specifically to support unlimited true
back-to-back read or write operations without the insertion of
wait states. The CY7C1471V25, CY7C1473V25, and
CY7C1475V25 are equipped with the advanced No Bus
Latency (NoBL) logic required to enable consecutive read or
write operations with data transferred on every clock cycle.
This feature dramatically improves the throughput of data
through the SRAM, especially in systems that require frequent
write-read transitions.
All synchronous inputs pass through input registers controlled
by the rising edge of the clock. The clock input is qualified by
the Clock Enable (CEN) signal, which when deasserted
suspends operation and extends the previous clock cycle.
Maximum access delay from the clock rise is 6.5 ns (133-MHz
device).
Write operations are controlled by two or four Byte Write Select
(BW
X
) and a Write Enable (WE) input. All writes are conducted
with on-chip synchronous self timed write circuitry.
Three synchronous Chip Enables (CE
1
, CE
2
, CE
3
) and an
asynchronous Output Enable (OE) provide easy bank
selection and output tri-state control. To avoid bus contention,
the output drivers are synchronously tri-stated during the data
portion of a write sequence.
Selection Guide
133 MHz
100 MHz
Unit
Maximum Access Time
6.5
8.5
ns
Maximum Operating Current
305
275
mA
Maximum CMOS Standby Current
120
120
mA
Note
1. For best practice recommendations, refer to the Cypress application note
AN1064, SRAM System Guidelines
.
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