19/21/25/29/
CY7C419/21/25/29/33
256/512/1K/2K/4K x 9 Asynchronous FIFO
Each FIFO memory is organized such that the data is read in
the same sequential order that it was written. Full and Empty
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)
flags are provided to prevent overrun and underrun. Three ad-
ditional 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.
• 4K x 9 (CY7C433)
• Dual-ported RAM cell
• High-speed 50.0-MHz read/write independent of
depth/width
• Low operating power: ICC = 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
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 stan-
dalone and width expansion configurations. In the depth ex-
pansion 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.
• Pin compatible and functionally equivalent to IDT7200,
IDT7201, IDT7202, IDT7203, IDT7204, AM7200, AM7201,
AM7202, AM7203, and AM7204
Functional Description
The CY7C419, CY7C420, CY7C421, CY7C424, CY7C425,
CY7C428, CY7C429, CY7C432, and CY7C433 are fabricated
using an advanced 0.65-micron P-well CMOS technology. In-
put ESD protection is greater than 2000V and latch-up is pre-
vented by careful layout and guard rings.
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.
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
Document #: 38-06001 Rev. *A
Revised December 30, 2002