LMC6772AIM NSC [National Semiconductor], LMC6772AIM Datasheet - Page 8

• Manufacturer Part Number: LMC6772AIM
• Description: Dual Micropower Rail-To-Rail Input CMOS Comparator with Open Drain Output
• Manufacturer: NSC [National Semiconductor]

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Typical Applications
One-Shot Multivibrator
A monostable multivibrator has one stable state in which it
can remain indefinitely. It can be triggered externally to an-
other quasi-stable state. A monostable multivibrator can thus
be used to generate a pulse of desired width.
The desired pulse width is set by adjusting the values of C
and R
termine the magnitude of the input trigger pulse. The
LMC6772 will change state when V
vides a rapid discharge path for capacitor C
end of the pulse. The diode also prevents the non-inverting
input from being driven below ground.
Bi-Stable Multivibrator
A bi-stable multivibrator has two stable states. The reference
voltage is set up by the voltage divider of R
applied to the SET terminal will switch the output of the com-
parator high. The resistor divider of R
clamps the non-inverting input to a voltage greater than the
reference voltage. A pulse applied to RESET will now toggle
the output low.
4
. The resistor divider of R
FIGURE 5. One-Shot Multivibrator
FIGURE 6. Bi-Stable Multivibrator
1
and R
(Continued)
1
<
2
1
, R
can be used to de-
V
2
2
. Diode D
2
and R
4
, and R
to reset at the
3
DS012347-30
. A pulse
DS012347-28
5
2
now
pro-
2
8
Zero Crossing Detector
A voltage divider of R
age V
tance of R
when V
−0.7V. The voltage divider of R
from going below ground. A small amount of hysteresis is
setup to ensure rapid output voltage transitions.
Oscillator
Figure 8 shows the application of the LMC6772 in a square
wave generator circuit. The total hysteresis of the loop is set
by R
discharge paths for the capacitor C. The charge path is set
through R
the RC time constant of R
path for the capacitor is set by R
between the pulses can be changed by varying R
pulse width can be altered by R
put can be changed by varying both R
1
1
, R
at the non-inverting input. By making the series resis-
IN
2
4
= 0. Diode D
1
and R
FIGURE 8. Square Wave Generator
FIGURE 7. Zero Crossing Detector
and D
and R
3
. R
1
2
. So, the pulse width t
equal to R
4
4
and R
and R
1
insures that V
4
and C. Similarly, the discharge
5
5
provide separate charge and
5
establishes a reference volt-
, the comparator will switch
4
2
5
. The frequency of the out-
and R
and D
4
3
3
and R
2
never drops below
1
. Thus, the time t
then prevents V
is determined by
5
.
DS012347-29
5
, and the
DS012347-31
2
2