SN74LS123M ON Semiconductor, SN74LS123M Datasheet - Page 3

• Manufacturer Part Number: SN74LS123M
• Manufacturer: ON Semiconductor

Specifications of SN74LS123M

• Logic Family: LS
• High Level Output Current: -400uA
• Low Level Output Current: 8mA
• Number Of Elements: 2
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (max): 5.25V
• Operating Supply Voltage (typ): 5V
• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Technology: Bipolar
• Abs. Propagation Delay Time: 56ns
• Operating Supply Voltage (min): 4.75V
• Lead Free Status / RoHS Status: Compliant

components, C
For values of C
V and V
If C
connection to ground, however for the best system
performance C
monostable as possible with a minimum amount of
inductance between the R
pin. Good groundplane and adequate bypassing should be
designed into the system for optimum performance to ensure
that no false triggering occurs.
to ground on the LS122 and LS123, but not on the LS221.
Therefore, if C
substitution of a LS221 onto a LS123 socket will cause the
LS221 to become non-functional.
capacitance application and should not be used on the LS122
and LS123.
Variations on V
change, as can the temperature of the LS123, LS122.
LS122 FUNCTIONAL TABLE
The output pulse t
The C
Care should be taken to keep R
It should be noted that the C
The switching diode is not needed for electrolytic
To find the value of K for C
ext
CLEAR
is on pF and R
X
X
X
H
H
H
H
H
H
H
↑
↑
L
ext
RC
t
W
terminal of the LS122 and LS123 is an internal
TYPICAL APPLICATION DATA
= 5.0 V (see Figures 1, 2, and 3) is given by
= K R
ext
ext
ext
A1
ext
CC
X
H
X
X
X
X
H
X
L
L
↓
↓
L
should be hard-wired to ground.
INPUTS
and R
≥ 1000 pF, the output pulse at V
ext
or V
is hard-wired externally to ground,
ext
C
W
A2
ext
H
H
is in kΩ then t
X
X
X
X
X
L
L
↓
↓
X
L
ext
RC
ext
is a function of the external
where K is nominally 0.45
or C
/C
ext
can cause the value of K to
ext
ext
B1
X
X
X
H
H
H
H
H
H
H
L
↑
↑
≥ 1000 pF, refer to Figure 4.
ext
pin is internally connected
ext
junction and the R
and R
and C
B2
W
X
X
X
H
H
H
H
H
H
H
L
↑
↑
is in nanoseconds.
int
ext
on the LS122.
Q
OUTPUTS
L
L
L
L
as close to the
CC
ext
Q
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H
H
H
H
= 5.0
/C
ext
3
Figures 5 and 6 show the behavior of the circuit shown in
Figures 1 and 2 if separate power supplies are used for V
and V
vary with V
R
included in the graph.
change in K with respect to R
to determine the output pulse width. Figure 9 shows how K
will change for C
to the same power supply. The pulse width t
nanoseconds is approximated by
t
include a variable resistor between V
or between V
and 12 show how this can be done. R
kept as close to the monostable as possible.
occur before C
have any effect. The discharge time of C
is guaranteed to be less than 0.22 C
0.05 C
from various devices, it is suggested that C
≥ 1000 pF.
W
ext
As long as C
If C
In order to trim the output pulse width, it is necessary to
Retriggering of the part, as shown in Figure 3, must not
For the smallest possible deviation in output pulse widths
= 6 + 0.05 C
and C
RC
ext
ext
LS123 FUNCTIONAL TABLE
. If V
≤ 1000 pF the graph shown on Figure 8 can be used
(pF).
CLEAR
CC
ext
CC
X
X
H
H
↑
L
CC
ext
and temperature. Remember, the changes in
with temperature are not calculated and
ext
ext
and the R
ext
is tied to V
is discharged or the retrigger pulse will not
INPUTS
(pF) + 0.45 R
≥ 1000 pF and 5K ≤ R
≤ 1000 pF if V
A
H
X
X
↓
L
L
ext
RC
pin of the LS122. Figure 10, 11,
ext
, Figure 7 shows how K will
B
X
X
H
H
L
↑
ext
is negligible.
CC
ext
(kΩ) C
CC
OUTPUTS
and V
Q
L
L
L
ext
(pF) and is typically
and the R
ext
remote should be
RC
ext
ext
Q
in nanoseconds
H
H
H
are connected
+ 11.6 R
≤ 260K, the
ext
ext
/C
be kept
ext
W
ext
pin
CC
in