- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄370121 > 74191 (National Semiconductor Corporation) Synchronous Up/Down 4-Bit Binary Counter with Mode Control PDF資料下載
參數(shù)資料
| 型號(hào)： | 74191 |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | 通用總線功能 |
| 英文描述： | Synchronous Up/Down 4-Bit Binary Counter with Mode Control |
| 中文描述： | 同步向上/向下4位二進(jìn)制計(jì)數(shù)器的模式控制 |
| 文件頁數(shù)： | 1/6頁 |
| 文件大小： | 129K |
| 代理商： | 74191 |
TL/F/6562
5
June 1989
54191/DM54191/DM74191 Synchronous Up/Down
4-Bit Binary Counter with Mode Control
General Description
This circuit is a synchronous, reversible, up/down counter.
The 191 is a 4-bit binary counter. Synchronous operation is
provided by having all flip-flops clocked simultaneously so
that the outputs change simultaneously when so instructed
by the steering logic. This mode of operation eliminates the
output counting spikes normally associated with asynchro-
nous (ripple clock) counters.
The outputs of the four master-slave flip-flops are triggered
on a low-to-high level transition of the clock input, if the
enable input is low. A high at the enable input inhibits count-
ing. Level changes at either the enable input or the down/
up input should be made only when the clock input is high.
The direction of the count is determined by the level of the
down/up input. When low, the counter counts up and when
high, it counts down.
This counter is fully programmable; that is, the outputs may
be preset to either level by placing a low on the load input
and entering the desired data at the data inputs. The output
will change independent of the level of the clock input. This
feature allows the counters to be used as modulo-N dividers
by simply modifying the count length with the preset inputs.
The clock, down/up, and load inputs are buffered to lower
the drive requirement; which significantly reduces the num-
ber of clock drivers, etc., required for long parallel words.
Two outputs have been made available to perform the cas-
cading function: ripple clock and maximum/minimum count.
The latter output produces a high-level output pulse with a
duration approximately equal to one complete cycle of the
clock when the counter overflows or underflows. The ripple
clock output produces a low-level output pulse equal in
width to the low-level portion of the clock input when an
overflow or underflow condition exists. The counters can be
easily cascaded by feeding the ripple clock output to the
enable input of the succeeding counter if parallel clocking is
used, or to the clock input if parallel enabling is used. The
maximum/minimum count output can be used to accom-
plish look-ahead for high-speed operation.
Features
Y
Single down/up count control line
Y
Count enable control input
Y
Ripple clock output for cascading
Y
Asynchronously presettable with load control
Y
Parallel outputs
Y
Cascadable for n-bit applications
Y
Alternate Military/Aerospace device (54191) is avail-
able. Contact a National Semiconductor Sales Office/
Distributor for specifications.
Connection Diagram
Dual-In-Line Package
TL/F/6562–1
Order Number 54191DMQB, 54191FMQB,
DM54191J, DM54191W or DM74191N
See NS Package Number J16A, N16E or W16A
C
1995 National Semiconductor Corporation
RRD-B30M105/Printed in U. S. A.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 74191 | Synchronous 4-Bit Up/Down Counter with Mode Control |
| 74195 | universal 4-bit shift reguster |
| 74195DC | Precision, Micropower Operational Amplifier; Package: SOIC; No of Pins: 8; Temperature Range: Industrial |
| 74195FC | UNIVERSAL 4-BIT SHIFT REGISTER |
| 74195PC | UNIVERSAL 4-BIT SHIFT REGISTER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 74191 WAF | 制造商:Texas Instruments 功能描述: |
| 74191-0002 | 功能描述:標(biāo)準(zhǔn)卡緣連接器 CARD EDGE CONN 300P micrprocessor RoHS:否 制造商:3M Electronic Solutions Division 系列:SPD08 產(chǎn)品類型:Contacts 位置/觸點(diǎn)數(shù)量:60 安裝角:Straight 電路板厚度: 安裝風(fēng)格:SMD/SMT 節(jié)距:8 mm 外殼材料:Liquid Crystal Polymer (LCP) 觸點(diǎn)材料:Copper Alloy 觸點(diǎn)電鍍:Gold |
| 74191-0003 | 制造商:MOLEX 制造商全稱:Molex Electronics Ltd. 功能描述:High Speed Edgecard Connector in Ground Signal Format for High Performance Applications |
| 74191-0004 | 制造商:MOLEX 制造商全稱:Molex Electronics Ltd. 功能描述:High Speed Edgecard Connector in Ground Signal Format for High Performance Applications |
| 74191-0005 | 制造商:MOLEX 制造商全稱:Molex Electronics Ltd. 功能描述:High Speed Edgecard Connector in Ground Signal Format for High Performance Applications |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。