4-Mbit (256K x 18) Flow-Through Sync SRAM
CY7C1325G
Cypress Semiconductor Corporation
•
198 Champion Court
•
San Jose
, CA 95134-1709
•
408-943-2600
Document #: 38-05518 Rev. *D
Revised July 4, 2006
Features
• 256K x 18 common I/O
• 3.3V core power supply (VDD)
• 2.5V or 3.3V I/O power supply (VDDQ)
• Fast clock-to-output times
— 6.5 ns (133-MHz version)
• Provide high-performance 2-1-1-1 access rate
• User-selectable burst counter supporting Intel®
Pentium® interleaved or linear burst sequences
• Separate processor and controller address strobes
• Synchronous self-timed write
• Asynchronous output enable
• Available in lead-free 100-Pin TQFP package, lead-free
and non-lead-free 119-Ball BGA package
• “ZZ” Sleep Mode option
Functional Description[1]
The CY7C1325G is a 256 K x 18 synchronous cache RAM
designed to interface with high-speed microprocessors with
minimum glue logic. Maximum access delay from clock rise is
6.5 ns (133-MHz version). A 2-bit on-chip counter captures the
first address in a burst and increments the address automati-
cally for the rest of the burst access. All synchronous inputs
are gated by registers controlled by a positive-edge-triggered
Clock Input (CLK). The synchronous inputs include all
addresses, all data inputs, address-pipelining Chip Enable
(CE1), depth-expansion Chip Enables (CE2 and CE3), Burst
Control inputs (ADSC, ADSP, and ADV), Write Enables
(BW[A:B], and BWE), and Global Write (GW). Asynchronous
inputs include the Output Enable (OE) and the ZZ pin.
The CY7C1325G allows either interleaved or linear burst
sequences, selected by the MODE input pin. A HIGH selects
an interleaved burst sequence, while a LOW selects a linear
burst sequence. Burst accesses can be initiated with the
Processor Address Strobe (ADSP) or the cache Controller
Address Strobe (ADSC) inputs.
Addresses and chip enables are registered at rising edge of
clock when either Address Strobe Processor (ADSP) or
Address Strobe Controller (ADSC) are active. Subsequent
burst addresses can be internally generated as controlled by
the Advance pin (ADV).
The CY7C1325G operates from a +3.3V core power supply
while all outputs may operate with either a +2.5 or +3.3V
supply.
All
inputs
and
outputs
are
JEDEC-standard
JESD8-5-compatible.
Note:
1. For best-practices recommendations, please refer to the Cypress application note System Design Guidelines on www.cypress.com.
Logic Block Diagram
ADDRESS
REGISTER
ADV
CLK
BURST
COUNTER AND
LOGIC
CLR
Q1
Q0
ADSC
CE1
OE
SENSE
AMPS
MEMORY
ARRAY
ADSP
OUTPUT
BUFFERS
INPUT
REGISTERS
MODE
CE2
CE3
GW
BWE
A0,A1,A
BWB
BWA
DQB,DQPB
WRITE REGISTER
DQA,DQPA
WRITE REGISTER
ENABLE
REGISTER
A[1:0]
DQs
DQPA
DQPB
DQB,DQPB
WRITE DRIVER
DQA,DQPA
WRITE DRIVER
SLEEP
CONTROL
ZZ
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