327
CY7C1327B
256K x 18 Synchronous-Pipelined Cache RAM
The CY7C1327B I/O pins can operate at either the 2.5V or the
3.3V level. The I/O pins are 3.3V tolerant when VDDQ=2.5V.
Features
• Supports 100-MHz bus for Pentium and PowerPC™
operations with zero wait states
• Fully registered inputs and outputs for pipelined
operation
• 256K by 18 common I/O architecture
• 3.3V core power supply
• 2.5V / 3.3V I/O operation
All synchronous inputs pass through input registers controlled
by the rising edge of the clock. All data outputs pass through
output registers controlled by the rising edge of the clock. Max-
imum access delay from the clock rise is 3.5 ns (166-MHz
device).
The CY7C1327B supports either the interleaved burst se-
quence used by the Intel Pentium processor or a linear burst
sequence used by processors such as the PowerPC. The
burst sequence is selected through the MODE pin. Accesses
can be initiated by asserting either the Processor Address
Strobe (ADSP) or the Controller Address Strobe (ADSC) at
clock rise. Address advancement through the burst sequence
is controlled by the ADV input. A 2-bit on-chip wraparound
burst counter captures the first address in a burst sequence
and automatically increments the address for the rest of the
burst access.
• Fast clock-to-output times
— 3.5 ns (for 166-MHz device)
— 4.0 ns (for 133-MHz device)
— 5.5 ns (for 100-MHz device)
• User-selectable burst counter supporting Intel
Pentium interleaved or linear burst sequences
• Separate processor and controller address strobes
• Synchronous self-timed writes
• Asynchronous Output Enable
• JEDEC-standard 100 TQFP pinout
Byte write operations are qualified with the four Byte Write
Select (BW[1:0]) inputs. A Global Write Enable (GW) overrides
all byte write inputs and writes data to all four bytes. All writes
are conducted with on-chip synchronous self-timed write cir-
cuitry.
• “ZZ” Sleep Mode option and Stop Clock option
Functional Description
Three synchronous Chip Selects (CE1, CE2, CE3) and an
asynchronous Output Enable (OE) provide for easy bank se-
lection and output three-state control. In order to provide prop-
er data during depth expansion, OE is masked during the first
clock of a read cycle when emerging from a deselected state.
The CY7C1327B is a 3.3V, 256K by 18 synchronous-pipelined
cache SRAM designed to support zero wait state secondary
cache with minimal glue logic.
MODE
Logic Block Diagram
2
(A
)
[1;0]
Q
Q
CLK
ADV
ADSC
0
BURST
COUNTER
CE
CLR
1
ADSP
Q
16
18
ADDRESS
REGISTER
CE
D
256KX18
MEMORY
ARRAY
A
[17:0]
18
16
GW
DQ[15:8], DP[1]
BYTEWRITE
REGISTERS
D
Q
BWE
BW
1
DQ[7:0], DP[0]
BYTEWRITE
REGISTERS
D
Q
BW
0
18
18
CE
2
1
CE
D
CE
Q
ENABLE CE
REGISTER
CE
3
D
Q
OUTPUT
INPUT
REGISTERS
CLK
ENABLE DELAY
REGISTER
REGISTERS
CLK
OE
ZZ
SLEEP
CONTROL
DQ
[15:0]
[1:0]
DP
Cypress Semiconductor Corporation
Document #: 38-05140 Rev. *B
•
3901 North First Street
•
San Jose, CA 95134
•
408-943-2600
Revised January 18, 2003