CY7C1357A
CY7C1355A
256K x 36/512K x 18 Synchronous Flow-Thru
SRAM with NoBL™ Architecture
inputs include all addresses, all data inputs, depth-expansion
Chip Enables (CE, CE2, and CE3), Cycle Start Input (ADV/LD),
Clock Enable (CEN), Byte Write Enables (BWa, BWb, BWc,
and BWd), and read-write control (WEN). BWc and BWd apply
to CY7C1355A/GVT71256ZB36 only.
Features
• Zero Bus Latency, no dead cycles between write and
read cycles
• Fast access times: 2.5 ns, 3.0 ns, and 3.5 ns
• Fast clock speed: 133, 117, and 100 MHz
• Fast OE access time: 6.5, 7.0, 7.5, and 8.0 ns
• Internally synchronized registered outputs eliminate
the need to control OE
Address and control signals are applied to the SRAM during
one clock cycle, and one cycle later, its associated data
occurs, either read or write.
A
Clock Enable (CEN) pin allows operation of the
CY7C1355A/CY7C1357A/GVT71256ZB36/GVT71512ZB18
to be suspended as long as necessary. All synchronous inputs
are ignored when (CEN) is HIGH and the internal device
registers will hold their previous values.
• 3.3V –5% and +5% power supply
• 3.3V or 2.5V I/O supply
• Single WEN (READ/WRITE) control pin
• Positive clock-edge triggered, address, data, and
control signal registers for fully pipelined applications
• Interleaved or linear four-word burst capability
• Individual byte write (BWa–BWd) control (may be tied
LOW)
• CEN pin to enable clock and suspend operations
• Three chip enables for simple depth expansion
• Automatic Power-down fearture available using ZZ
mode or CE deselect.
There are three Chip Enable pins (CE, CE2, CE3) that allow
the user to deselect the device when desired. If any one of
these three are not active when ADV/LD is LOW, no new
memory operation can be initiated and any burst cycle in
progress is stopped. However, any pending data transfers
(read or write) will be completed. The data bus will be in
high-impedance state one cycle after chip is deselected or a
write cycle is initiated.
The
CY7C1355A/GVT71256ZB36
and
CY7C1357A/
GVT71512ZB18 have an on-chip 2-bit burst counter. In the
burst mode, the CY7C1355A/GVT71256ZB36 and
CY7C1357A/GVT71512ZB18 provide four cycles of data for a
single address presented to the SRAM. The order of the burst
sequence is defined by the MODE input pin. The MODE pin
selects between linear and interleaved burst sequence. The
ADV/LD signal is used to load a new external address
(ADV/LD = LOW) or increment the internal burst counter
(ADV/LD = HIGH)
• JTAG boundary scan
• Low-profile 119-bump, 14-mm × 22-mm BGA (Ball Grid
Array) and 100-pin TQFP packages
Functional Description
The
CY7C1355A/GVT71256ZB36
and
CY7C1357A/
GVT71512ZB18 SRAMs are designed to eliminate dead
cycles when transitions from READ to WRITE or vice versa.
These SRAMs are optimized for 100 percent bus utilization
and achieves Zero Bus Latency (ZBL). They integrate 262,144
× 36 and 524,288 × 18 SRAM cells, respectively, with
advanced synchronous peripheral circuitry and a 2-bit counter
for internal burst operation. These employ high-speed, low
power CMOS designs using advanced triple-layer polysilicon,
double-layer metal technology. Each memory cell consists of
Six transistors.
Output Enable (OE), Sleep Enable (ZZ) and burst sequence
select (MODE) are the asynchronous signals. OE can be used
to disable the outputs at any given time. ZZ may be tied to
LOW if it is not used.
Four pins are used to implement JTAG test capabilities. The
JTAG circuitry is used to serially shift data to and from the
device. JTAG inputs use LVTTL/LVCMOS levels to shift data
during this testing mode of operation.
All synchronous inputs are gated by registers controlled by a
positive-edge-triggered Clock Input (CLK). The synchronous
Selection Guide
7C1355A-133
71256ZB36-6.5
7C1357A-133
71512ZB18-6.5
7C1355A-117
71256ZB36-7
7C1357A-117
71512ZB18-7
7C1355A-100
71256ZB36-7.5
7C1357A-100
71512ZB18-7.5
7C1355A1-100
71256ZB36-8
7C1357A1-100
71512ZB18-8
Unit
ns
Maximum Access Time
6.5
410
30
7
7.5
350
30
8
Maximum Operating Current
Maximum CMOS Standby Current
385
30
350
30
mA
mA
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
Document #: 38-05265 Rev. **
Revised July 11, 2002