SN74ACT2235
1024 × 9 × 2
ASYNCHRONOUS BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY
SCAS148F – DECEMBER 1990 – REVISED JUNE 2003
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D
Independent Asynchronous Inputs and
Outputs
D
Low-Power Advanced CMOS Technology
D
Bidirectional
D
Dual 1024 by 9 Bits
D
Programmable Almost-Full/Almost-Empty
Flag
D
Empty, Full, and Half-Full Flags
D
Access Times of 25 ns With a 50-pF Load
D
Data Rates up to 50 MHz
D
Fall-Through Times of 22 ns Maximum
D
High Output Drive for Direct Bus Interface
D
Package Options Include 44-Pin Plastic
Leaded Chip Carriers (FN) and 64-Pin Thin
Quad Flat (PAG, PM) Packages
description
A FIFO memory is a storage device that allows data to be written into and read from its array at independent
data rates. The SN74ACT2235 is arranged as two 1024 × 9-bit FIFOs for high speed and fast access times.
It processes data at rates up to 50 MHz, with access times of 25 ns in a bit-parallel format.
The SN74ACT2235 consists of bus-transceiver circuits, two 1024 × 9-bit FIFOs, and control circuitry arranged
for multiplexed transmission of data directly from the data bus or from the internal FIFO memories. Enable (GAB
and GBA) inputs are provided to control the transceiver functions. The select-control (SAB and SBA) inputs are
provided to select whether real-time or stored data is transferred. The circuitry used for select control eliminates
the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data.
Figure 2 shows the eight fundamental bus-management functions that can be performed with the
SN74ACT2235.
For more information on this device family, see the application report, 1K × 9 × 2 Asynchronous FIFO
SN74ACT2235, literature number SCAA010.
The SN74ACT2235 is characterized for operation from 0°C to 70°C.
B2
B3
B4
V
CC
B5
B6
B7
B8
GND
AF/AEB
HFB
39
38
37
36
35
34
33
32
31
30
29
18 19
7
8
9
10
11
12
13
14
15
16
17
A3
A4
V
CC
A5
A6
A7
A8
GND
AF/AEA
HFA
LDCKA
20 21 22 23
FN PACKAGE
(TOP VIEW)
GAB
GND
B0
B1
543 21644
A2
A1
A0
GND
GBA
SBA
SAB
EMPTYA
UNCKA
FULLB
LDCKB
FULLA
UNCKB
EMPTYB
DAF
RSTA
RSTB
DBF
42 41 4043
24 25 26 27 28
Copyright 2003, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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