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参数资料
| 型号： | SN74LS123N |
| 厂商： | FREESCALE SEMICONDUCTOR INC |
| 元件分类： | 谐振器 |
| 英文描述： | LS SERIES, DUAL MONOSTABLE MULTIVIBRATOR, PDIP16 |
| 封装： | PLASTIC, DIP-16 |
| 文件页数： | 3/10页 |
| 文件大小： | 275K |
| 代理商： | SN74LS123N |
5-198
FAST AND LS TTL DATA
SN54/74LS122
SN54/74LS123
LS122
FUNCTIONAL TABLE
INPUTS
OUTPUTS
CLEAR
A1
A2
B1
B2
Q
L
X
L
H
X
H
X
L
H
X
L
X
L
H
X
L
H
L
X
↑
H
L
X
H
↑
H
X
L
↑
H
X
L
H
↑
H
↓
H
↓
H
↓
H
↑
L
X
H
↑
X
L
H
LS123
FUNCTIONAL TABLE
INPUTS
OUTPUTS
CLEAR
A
B
Q
L
X
L
H
X
H
X
L
H
X
L
H
L
↑
H
↓
H
↑
L
H
TYPICAL APPLICATION DATA
The output pulse tW is a function of the external compo-
nents, Cext and Rext or Cext and Rint on the LS122. For values
of Cext ≥ 1000 pF, the output pulse at VCC = 5.0 V and VRC =
5.0 V (see Figures 1, 2, and 3) is given by
tW = K Rext Cext where K is nominally 0.45
If Cext is on pF and Rext is in k then tW is in nanoseconds.
The Cext terminal of the LS122 and LS123 is an internal
connection to ground, however for the best system perfor-
mance Cext should be hard-wired to ground.
Care should be taken to keep Rext and Cext as close to the
monostable as possible with a minimum amount of inductance
between the Rext/Cext junction and the Rext/Cext pin. Good
groundplane and adequate bypassing should be designed
into the system for optimum performance to insure that no
false triggering occurs.
It should be noted that the Cext pin is internally connected
to ground on the LS122 and LS123, but not on the LS221.
Therefore, if Cext is hard-wired externally to ground, substitu-
tion of a LS221 onto a LS123 socket will cause the LS221 to
become non-functional.
The switching diode is not needed for electrolytic capaci-
tance application and should not be used on the LS122 and
LS123.
To find the value of K for Cext ≥ 1000 pF, refer to Figure 4.
Variations on VCC or VRC can cause the value of K to change,
as can the temperature of the LS123, LS122. Figures 5 and
6 show the behavior of the circuit shown in Figures 1 and 2 if
separate power supplies are used for VCC and VRC. If VCC is
tied to VRC, Figure 7 shows how K will vary with VCC and
temperature. Remember, the changes in Rext and Cext with
temperature are not calculated and included in the graph.
As long as Cext ≥ 1000 pF and 5K ≤ Rext ≤ 260K
(SN74LS122 / 123) or 5K
≤ Rext ≤ 160 K (SN54LS122/123),
the change in K with respect to Rext is negligible.
If Cext ≤ 1000 pF the graph shown on Figure 8 can be used
to determine the output pulse width. Figure 9 shows how K will
change for Cext≤1000pFifVCCandVRC areconnectedtothe
same power supply. The pulse width tW in nanoseconds is
approximated by
tW = 6 + 0.05 Cext (pF) + 0.45 Rext (k) Cext + 11.6 Rext
In order to trim the output pulse width, it is necessary to
include a variable resistor between VCC and the Rext/Cext pin
or between VCC and the Rext pin of the LS122. Figure 10, 11,
and 12 show how this can be done. Rext remote should be kept
as close to the monostable as possible.
Retriggering of the part, as shown in Figure 3, must not
occur before Cext is discharged or the retrigger pulse will not
have any effect. The discharge time of Cext in nanoseconds is
guaranteed to be less than 0.22 Cext (pF) and is typically 0.05
Cext (pF).
For the smallest possible deviation in output pulse widths
from various devices, it is suggested that Cext be kept
≥ 1000 pF.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SN74LS123N | 制造商:Texas Instruments 功能描述:Multivibrator Logic IC |
| SN74LS123NDS | 制造商:Motorola Inc 功能描述:Multivibrator, Monostable Type, 16 Pin, Plastic, DIP |
| SN74LS123NE4 | 功能描述:单稳态多谐振荡器 Dual retrig monostbl multivibrators RoHS:否 制造商:Texas Instruments 每芯片元件:1 逻辑系列:LVC 逻辑类型:Monostable Multivibrator 封装 / 箱体:SSOP-8 传播延迟时间:18.6 ns 高电平输出电流:- 32 mA 低电平输出电流:32 mA 电源电压-最大:5.5 V 电源电压-最小:1.65 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
| SN74LS123NSR | 功能描述:单稳态多谐振荡器 Dual retrig monostbl multivibrators RoHS:否 制造商:Texas Instruments 每芯片元件:1 逻辑系列:LVC 逻辑类型:Monostable Multivibrator 封装 / 箱体:SSOP-8 传播延迟时间:18.6 ns 高电平输出电流:- 32 mA 低电平输出电流:32 mA 电源电压-最大:5.5 V 电源电压-最小:1.65 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
| SN74LS123NSRG4 | 功能描述:单稳态多谐振荡器 Dual retrig monostbl multivibrators RoHS:否 制造商:Texas Instruments 每芯片元件:1 逻辑系列:LVC 逻辑类型:Monostable Multivibrator 封装 / 箱体:SSOP-8 传播延迟时间:18.6 ns 高电平输出电流:- 32 mA 低电平输出电流:32 mA 电源电压-最大:5.5 V 电源电压-最小:1.65 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
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