參數(shù)資料
型號(hào): 74F191
廠商: National Semiconductor Corporation
元件分類: 通用總線功能
英文描述: Up/Down Binary Counter with Preset and Ripple Clock
中文描述: 向上/向下二進(jìn)制計(jì)數(shù)器的預(yù)置和波紋時(shí)鐘
文件頁(yè)數(shù): 5/14頁(yè)
文件大?。?/td> 104K
代理商: 74F191
Philips Semiconductors
Product specification
74F191
Up/Down binary counter with reset and ripple clock
1995 Jul 17
5
APPLICATIONS
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
U/D
CE
CP
TC
TC
TC
RC
RC
RC
RC
RC
RC
DIRECTION CONTROL
CLOCK
ENABLE
ENABLE
DIRECTION CONTROL
CLOCK
ENABLE
DIRECTION CONTROL
CLOCK
a. N-Stage Counter Using Ripple Clock
b. Synchronous N-Stage Counter with Common Clock Using Ripple/Clock
c. Synchronous N-Stage Counter with Common Clock and Terminal Count
* = Carry Gate
*
*
SF00733
Figure 1.
The 74F191 simplifies the design of multi-stage counters, as
indicated in Figure 1, each RC output is used as the clock input for
the next higher stage. When the clock source has a limited drive
capability this configuration is particularly advantageous, since the
clock source drives only the first stage. It is only necessary to inhibit
the first stage to prevent counting in all stages, since a High signal
on CE inhibits the RC output pulse as indicated in the Mode Select
Table. The timing skew between state changes in the first and last
stages is represented by the cumulative delay of the clock as it
ripples through the preceding stages. This is a disadvantage of the
configuration in some applications.
Figure 1b shows a method of causing state changes to occur
simultaneously in all stages. The RC output signals propagate in
ripple fashion and all clock inputs are driven in parallel. The Low
state duration of the clock in this configuration must be long enough
to allow the negative-going edge of the RC signal to ripple through
to the last stage before the clock goes High. Since the RC output of
any package goes High shortly after its clock input goes High, there
is no such restriction on the High state duration of the clock.
In Figure 1c, the configuration shown avoids ripple delays and their
associated restrictions. The combined TC signals from all the
preceding stages forms the CE input signal for a given stage. An
enable signal must also be included in each carry gate in order to
inhibit counting. The TC output of a given stage is not affected by its
own CE, therefore, the simple inhibit scheme of Figure 1a and 1b
does not apply.
相關(guān)PDF資料
PDF描述
74F191SC Up/Down Binary Counter with Preset and Ripple Clock
74F191SJ Up/Down Binary Counter with Preset and Ripple Clock
74F191PC Up/Down Binary Counter with Preset and Ripple Clock
74F191 Up/Down Binary Counter with Preset and Ripple Clock
74F191SC Up/Down Binary Counter with Preset and Ripple Clock
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
74F191_07 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Up/Down Binary Counter with Preset and Ripple Clock
74F191DC 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Synchronous Up/Down Counter
74F191DCQB 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Up/Down Binary Counter with Preset and Ripple Clock
74F191DCX 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Up/Down Binary Counter with Preset and Ripple Clock
74F191DMQB 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Up/Down Binary Counter with Preset and Ripple Clock