256/512/1K/2K/4K x 9 Asynchronous FIFO
CY7C419/21/25/29/33
Cypress Semiconductor Corporation • 3901 North First Street • San Jose, CA 95134 • 408-943-2600
Document #: 38-06001 Rev. *B Revised June 30, 2005
Features
• Asynchronous first-in first-out (FIFO) buffer memories
• 256 x 9 (CY7C419)
• 512 x 9 (CY7C421)
• 1K x 9 (CY7C425)
• 2K x 9 (CY7C429)
• 4K x 9 (CY7C433)
• Dual-ported RAM cell
• High-speed 50.0-MHz read/write independent of
depth/width
• Low operating power: I
CC
= 35 mA
• Empty and Full flags (Half Full flag in standalone)
• TTL compatible
• Retransmit in standalone
• Expandable in width
• PLCC, 7x7 TQFP, SOJ, 300-mil and 600-mil DIP
• Pb-Free Packages Available
• Pin compatible and functionally equivalent to IDT7200,
IDT7201, IDT7202, IDT7203, IDT7204, AM7200, AM7201,
AM7202, AM7203, and AM7204
Functional Description
The CY7C419, CY7C420/1, CY7C424/5, CY7C428/9, and
CY7C432/3 are first-in first-out (FIFO) memories offered in
600-mil wide and 300-mil wide packages. They are, respec-
tively, 256, 512, 1,024, 2,048, and 4,096 words by 9-bits wide.
Each FIFO memory is organized such that the data is read in
the same sequential order that it was written. Full and Empty
flags are provided to prevent overrun and underrun. Three
additional pins are also provided to facilitate unlimited
expansion in width, depth, or both. The depth expansion
technique steers the control signals from one device to
another in parallel, thus eliminating the serial addition of
propagation delays, so that throughput is not reduced. Data is
steered in a similar manner.
The read and write operations may be asynchronous; each
can occur at a rate of 50.0 MHz. The write operation occurs
when the write (W
) signal is LOW. Read occurs when read (R)
goes LOW. The nine data outputs go to the high-impedance
state when R is HIGH.
A Half Full (HF
) output flag is provided that is valid in the
standalone and width expansion configurations. In the depth
expansion configuration, this pin provides the expansion out
(XO
) information that is used to tell the next FIFO that it will be
activated.
In the standalone and width expansion configurations, a LOW
on the retransmit (RT
) input causes the FIFOs to retransmit
the data. Read enable (R
) and write enable (W) must both be
HIGH during retransmit, and then R
is used to access the data.
The CY7C419, CY7C420, CY7C421, CY7C424, CY7C425,
CY7C428, CY7C429, CY7C432, and CY7C433 are fabricated
using an advanced 0.65-micron P-well CMOS technology.
Input ESD protection is greater than 2000V and latch-up is
prevented by careful layout and guard rings.
CY7C419/21/25/29/33256/512/1K/2K/4K x 9 Asynchronous FIFO
