没有合适的资源?快使用搜索试试~ 我知道了~
TI-SN74ACT7808.pdf
需积分: 10 0 下载量 185 浏览量
2022-12-11
13:58:23
上传
评论 5
收藏 185KB PDF 举报
温馨提示
试读
14页
TI-SN74ACT7808.pdf
资源推荐
资源详情
资源评论
SN74ACT7808
2048 × 9 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS205D – FEBRUARY 1991 – REVISED APRIL 1998
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D
Load Clocks and Unload Clocks Can Be
Asynchronous or Coincident
D
2048 Words by 9 Bits
D
Low-Power Advanced CMOS Technology
D
Fast Access Times of 15 ns With a 50-pF
Load
D
Programmable Almost-Full/Almost-Empty
Flag
D
Expansion Logic for Depth Cascading
D
Empty, Full, and Half-Full Flags
D
Fall-Through Time of 20 ns Typical
D
Data Rates up to 50 MHz
D
3-State Outputs
D
Package Options Include 44-Pin Plastic
Leaded Chip Carrier (FN), 64-Pin Thin Quad
Flat (PM), and Reduced-Height 64-Pin Quad
Flat (PAG) 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 SN74ACT7808 is a 2048-word by 9-bit FIFO designed for high speed and fast access times.
It processes data at rates up to 50 MHz and access times of 15 ns in a bit-parallel format.
Data is written into memory on a low-to-high transition at the load-clock (LDCK) input and is read out on a
low-to-high transition at the unload-clock (UNCK) input. The memory is full when the number of words clocked
in exceeds the number of words clocked out by 2048. When the memory is full, LDCK signals have no effect
on the data residing in memory. When the memory is empty, UNCK signals have no effect.
Status of the FIFO memory is monitored by the full (FULL
), empty (EMPTY), half-full (HF), and
almost-full/almost-empty (AF/AE) flags. The FULL
output is low when the memory is full and high when the
memory is not full. The EMPTY
output is low when the memory is empty and high when it is not empty. The HF
output is high when the FIFO contains 1024 or more words and is low when it contains 1023 or fewer words.
The AF/AE status flag is a programmable flag. The first one or two low-to-high transitions of LDCK after reset
can be used to program the almost-empty offset value (X) and the almost-full offset value (Y) if program enable
(PEN
) is low. The AF/AE flag is high when the FIFO contains X or fewer words or (2048 – Y) or more words.
The AF/AE flag is low when the FIFO contains between (X + 1) and (2047 – Y) words.
A low level on the reset (RESET
) input resets the internal stack pointers and sets FULL high, AF/AE high, HF
low, and EMPTY
low. The Q outputs are not reset to any specific logic level.
The first word loaded into empty memory causes EMPTY
to go high and the data to appear on the Q outputs.
It is important to note that the first word does not have to be unloaded. Data outputs are noninverting with respect
to the data inputs and are in the high-impedance state when the output-enable (OE) input is low. OE does not
affect the output flags.
Cascading is easily accomplished in the word-width and word-depth directions. When not using the FIFO in
depth expansion, cascade enable (CASEN
) must be tied high.
The FIFO must be reset upon power up.
The SN74ACT7808 is characterized for operation from 0°C to 70°C.
Copyright 1998, 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.
SN74ACT7808
2048 × 9 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS205D – FEBRUARY 1991 – REVISED APRIL 1998
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Q1
V
CC
Q2
Q3
GND
Q4
V
CC
Q5
Q6
GND
Q7
39
38
37
36
35
34
33
32
31
30
29
7
8
9
10
11
12
13
14
15
16
17
D0
D1
D2
GND
D3
D4
D5
V
CC
D6
D7
D8
FN PACKAGE
(TOP VIEW)
XO
OE
GND
Q0
HF
AF/AE
GND
PEN
RESET
CASEN
UNCK
Q8
GND
LDCK
DP9
XI
FULL
EMPTY
FL
V
CC
V
CC
Q2
GND
GND
Q3
Q4
Q5
Q6
GND
Q7
GND
NC
D1
D2
GND
GND
D4
D8
NC
NC
D0
D3
NC
D5
V
CC
V
CC
V
CC
V
CC
D6
D7
Q1
PAG OR PM PACKAGE
(TOP VIEW)
NC
Q0
GND
GND
OE
XO
V
CC
V
CC
RESET
PEN
GND
GND
AF/AE
HF
V
CC
V
CC
NC
Q8
V
CC
V
CC
UNCK
CASEN
NC
FL
EMPTY
FULL
XI
DP9
LDCK
GND
GND
NC
V
CC
6 5 4 3 2 1 44 43 42 41 40
18 19 20 21 22 23 24 25 26 27 28
V
CC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
18 19 20 21 22 23 24 25 26 27 2817 29 30 31 32
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
NC – No internal connection
SN74ACT7808
2048 × 9 STROBED FIRST-IN, FIRST-OUT MEMORY
SCAS205D – FEBRUARY 1991 – REVISED APRIL 1998
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
logic symbol
†
0
7
D0
8
D1
9
D2
11
D3
12
D4
13
D5
15
D6
16
D7
8
17
D8
Q0
40
0
Q1
39
Q2
37
Q3
36
Q4
34
22
FULL
HF
5
HALF FULL
AF/AE
4
ALMOST FULL/EMPTY
23
EMPTY
Q5
32
Q6
31
Q7
29
Q8
28
8
Data
1
RESET
RESET
1
19
LDCK
LDCK
EN1
42
OE
EXPANSION IN
21
XI
Data
26
UNCK
UNCK
PEN PROGRAM ENABLE
2
FL FIRST LOAD
24
CASEN CASCADE ENABLE
25
DATA PIN 9
20
DP9
FULL
EMPTY
XO
43
EXPANSION OUT
Φ
FIFO 2048 × 9
SN74ACT7808
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the FN package.
剩余13页未读,继续阅读
资源评论
不觉明了
- 粉丝: 3138
- 资源: 5392
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
最新资源
- 一个用WPF实现的图片处理小工具,可进行图片裁剪、缩放、涂鸦、旋转、查看图片信息、保存
- python爱心代码高级(小白可实战).zip
- 基于Python实现的使用霍普菲尔德神经网络算法解决旅行商问题.zip
- LML9303G-VB一款SOT23封装P-Channel场效应MOS管
- 基于Python实现的使用自组织映射SOM解决旅行商问题.zip
- LML9301-VB一款SOT23封装P-Channel场效应MOS管
- LML9301G-VB一款SOT23封装P-Channel场效应MOS管
- FFmpeg-release-6.1源码
- 基于Python实现的多种启发式算法解决广义旅行商问题.zip
- LML6402-VB一款SOT23封装P-Channel场效应MOS管
资源上传下载、课程学习等过程中有任何疑问或建议,欢迎提出宝贵意见哦~我们会及时处理!
点击此处反馈
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功