PRELIMINARY
CY7C1471V25
CY7C1473V25
CY7C1475V25
72-Mbit (2M x 36/4M x 18/1M x 72) Flow-Through SRAM
with NoBL™ Architecture
Features
• No Bus Latency™ (NoBL™) architecture eliminates
dead cycles between write and read cycles.
• Can support 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 I/O power supply
• Fast clock-to-output times
— 6.5 ns (for 133-MHz device)
— 8.5 ns (for 100-MHz device)
• Clock Enable (CEN) pin to enable clock and suspend
operation
• Synchronous self-timed writes
• Asynchronous Output Enable
• Offered in JEDEC-standard lead-free 100 TQFP, and
165-ball fBGA packages for CY7C1471V25 and
CY7C1473V25. 209-ball fBGA package for
CY7C1475V25.
• Three chip enables for simple depth expansion.
• Automatic Power-down feature available using ZZ
mode or CE deselect.
• JTAG boundary scan for BGA and fBGA packages
• 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/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/Write operations with data being 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 the 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 for easy bank
selection and output tri-state control. In order to avoid bus
contention, the output drivers are synchronously tri-stated
during the data portion of a write sequence.
Selection Guide
133 MHz
Maximum Access Time
Maximum Operating Current
Maximum CMOS Standby Current
6.5
305
120
100 MHz
8.5
275
120
Unit
ns
mA
mA
Note:
1. For best-practices recommendations, please refer to the Cypress application note
System Design Guidelines
on www.cypress.com.
Cypress Semiconductor Corporation
Document #: 38-05287 Rev. *E
•
3901 North First Street
•
San Jose
,
CA 95134
•
408-943-2600
Revised December 5, 2004
stm32/stm8
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