LMV7291MG/NOPB National Semiconductor, LMV7291MG/NOPB Datasheet - Page 13

• Manufacturer Part Number: LMV7291MG/NOPB
• Description: IC COMPARATOR 1.8V R-R LP SC70-5
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: General Purposer

Specifications of LMV7291MG/NOPB

• Number Of Elements: 1
• Output Type: CMOS, Push-Pull, Rail-to-Rail
• Voltage - Supply: 1.8 V ~ 5 V, ±0.9 V ~ 2.5 V
• Mounting Type: Surface Mount
• Package / Case: 6-TSSOP (5 lead), SC-88A, SOT-353
• Comparator Type: General Purpose
• No. Of Comparators: 1
• Response Time: 880ns
• Ic Output Type: Push Pull
• Supply Current: 14µA
• Supply Voltage Range: 1.8V To 5V
• Amplifier Case Style: SC-70
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LMV7291MG; LMV7291MGTR

Typical Applications
SQUARE WAVE GENERATOR
A typical application for a comparator is as a square wave
oscillator. The circuit below generates a square wave whose
period is set by the RC time constant of the capacitor C
resistor R
signal propagation delay of the comparator, and by the ca-
pacitive loading at the output, which limits the output slew
rate.
4
. The maximum frequency is limited by the large
FIGURE 6. Negative Peak Detector
FIGURE 7. Squarewave Oscillator
(Continued)
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1
and
13
To analyze the circuit, consider it when the output is high.
That implies that the inverted input (V
non-inverting input (V
through R
non-inverting input. The value of V
If R
At this point the comparator switches pulling down the output
to the negative rail. The value of V
If R
The capacitor C
age V
comparator switches again, bringing it back to the initial
stage. The time period is equal to twice the time it takes to
discharge C
R
F = 1/(2.R
4
C
1
1
1
.ln2. Hence the formula for the frequency is:
= R
= R
C
decreases till it is equal to V
2
2
4,
4
= R
= R
.C
and the voltage V
1
1
3
3
.ln2)
from 2V
then V
then V
1
now discharges through R
A
). This causes the C
A1
A2
CC
= 2V
= V
/3 to V
CC
C
CC
increases till it is equal to the
/3
/3
CC
A
A
at this point is
/3, which is given by
at this point is
A2
C
, at which point the
) is lower than the
1
4
to get charged
, and the volt-
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