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Cypress Semiconductor |
CY7C4261V
CY7C4281V/CY7C4291V
16K/64K/128K × 9
Low-Voltage Deep Sync™ FIFOs
16K/64K/128K × 9 Low-Voltage Deep Sync™ FIFOs
Features
■ 3.3 V operation for low-power consumption and easy
integration into low-voltage systems
■ High-speed, low-power, first-in first-out (FIFO) memories
■ 16K × 9 (CY7C4261V)
■ 64K × 9 (CY7C4281V)
■ 128K × 9 (CY7C4291V)
■ 0.35-micron CMOS for optimum speed or power
■ High-speed 100-MHz operation (10-ns read/write cycle times)
■ Low power
❐ ICC = 25 mA
❐ ISB = 4 mA
■ Fully asynchronous and simultaneous read and write operation
■ Empty, full, and programmable Almost Empty and Almost Full
status flags
■ Output-enable (OE) pin
■ Independent read- and write-enable pins
■ Supports free-running 50% duty cycle clock inputs
■ Width-expansion capability
■ Pin-compatible 3.3 V solutions for CY7C4261/81/91
■ Pin-compatible density upgrade within the CY7C42X1V family
■ Pb-free packages available
Functional Description
The CY7C4261/81/91V are high-speed, low-power FIFO
memories with clocked read and write interfaces. All are nine bits
wide. The CY7C4261/81/91V are pin-compatible with the lower
densities in the CY7C42x1V Synchronous FIFO family.
Programmable features include Almost Full/Almost Empty flags.
These FIFOs provide solutions for a wide variety of data
buffering needs, including high-speed data acquisition,
multiprocessor interfaces, and communications buffering.
Selection Guide
These FIFOs have 9-bit input and output ports that are controlled
by separate clock and enable signals. The input port is controlled
by a free-running clock (WCLK) and two write-enable pins
(WEN1, WEN2/LD).
When WEN1 is LOW and WEN2/LD is HIGH, data is written into
the FIFO on the rising edge of the WCLK signal. While WEN1
and WEN2/LD are held active, data is continually written into the
FIFO on each WCLK cycle. The output port is controlled in a
similar manner by a free-running read clock (RCLK) and two
read-enable pins (REN1, REN2). In addition, the
CY7C4261/81/91V has an output-enable pin (OE). The read
(RCLK) and write (WCLK) clocks may be tied together for
single-clock operation or the two clocks may be run
independently for asynchronous read/write applications. Clock
frequencies up to 100 MHz are achievable. Depth expansion is
possible using one enable input for system control, while the
other enable is controlled by expansion logic to direct the flow of
data.
The CY7C4261/81/91V provides four status pins: Empty, Full,
Programmable Almost Empty, and Programmable Almost Full.
The Almost Empty/Almost Full flags are programmable to single
word granularity. The programmable flags default to Empty +7
and Full –7.
The flags are synchronous, that is, they change state relative to
either the read clock (RCLK) or the write clock (WCLK). When
entering or exiting the Empty and Almost Empty states, the flags
are updated exclusively by the RCLK. The flags denoting Almost
Full, and Full states are updated exclusively by WCLK. The
synchronous flag architecture guarantees that the flags maintain
their status for at least one cycle.
All configurations are fabricated using an advanced 0.35 μ
CMOS technology. Input ESD protection is greater than 2001 V,
and latch-up is prevented by the use of guard rings.
For a complete list of related documentation, click here.
Description
Maximum frequency
Maximum access time
Minimum cycle time
Minimum data or enable setup
Minimum data or enable hold
Maximum flag delay
Active power supply current (ICC1)
Commercial
7C4261/81V-10
100
8
10
3.5
0
8
25
7C4261/91V-15
66.7
10
15
4
0
10
25
Unit
MHz
ns
ns
ns
ns
ns
mA
Density
Package
CY7C4261V
16K × 9
32-pin PLCC
CY7C4281V
64K × 9
32-pin PLCC
CY7C4291V
128K × 9
32-pin PLCC
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 38-06013 Rev. *K
• San Jose, CA 95134-1709 • 408-943-2600
Revised September 15, 2016
CY7C4261V
CY7C4281V/CY7C4291V
Logic Block Diagram
D0–8
RIengpisutter
WCLK WEN1WEN2/LD
Write
Control
Write
Pointer
Dual Port
RAM Array
16K/
64Kx/1928K
PRreFoglgaisrgatemr
Flag
Logic
PRoienatedr
EF
PAE
PAF
FF
RS RLoegsiect
Tristate
Output Register
Q0–8
Read
Control
OE
RCLK REN1 REN2
Document Number: 38-06013 Rev. *K
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