Page 1
LMV931 Single / LMV932 Dual / LMV934 Quad
1.8V, RRIO Operational Amplifiers
LMV931 Single / LMV932 Dual / LMV934 Quad 1.8V, RRIO Operational Amplifiers
December 2002
General Description
The LMV931/LMV932/LMV934 are low voltage, low power
operational amplifiers. LMV931/LMV932/LMV934 are guaranteed to operate from +1.8V to +5.0V supply voltages and
have rail-to-rail input and output. LMV931/LMV932/LMV934
input common mode voltage extends 200mV beyond the
supplies which enables user enhanced functionality beyond
the supply voltage range. The output can swing rail-to-rail
unloaded and within 105mV from the rail with 600Ω load at
1.8V supply. The LMV931/LMV932/LMV934 are optimized to
work at 1.8V which make them ideal for portable two-cell
battery powered systems and single cell Li-Ion systems.
LMV931/LMV932/LMV934 exhibit excellent speed-power ratio, achieving 1.4MHz gain bandwidth product at 1.8V supply
voltage with very low supply current. The LMV931/LMV932/
LMV934 are capable of driving a 600Ω load and up to
1000pF capacitive load with minimal ringing. LMV931/
LMV932/LMV934 have a high DC gain of 101dB, making
them suitable for low frequency applications.
The single LMV931 is offered in space saving SC70-5 and
SOT23-5 packages. The dual LMV932 are in MSOP-8 and
SOIC-8 packages and the quad LMV934 are in TSSOP-14
and SOIC-14 packages. These small packages are ideal
solutions for area constrained PC boards and portable electronics such as cellular phones and PDAs.
Typical Application
Features
(Typical 1.8V Supply Values; Unless Otherwise Noted)
n Guaranteed 1.8V, 2.7V and 5V specifications
n Output swing
— w/600Ω load 80mV from rail
— w/2kΩ load 30mV from rail
n V
CM
n Supply current (per channel) 100µA
n Gain bandwidth product 1.4MHz
n Maximum V
n Ultra tiny packages
n Temperature range −40˚C to 125˚C
OS
200mV beyond rails
4.0mV
Applications
n Consumer communication
n Consumer computing
n PDAs
n Audio pre-amp
n Portable/battery-powered electronic equipment
n Supply current monitoring
n Battery monitoring
200326H0
© 2002 National Semiconductor Corporation DS200326 www.national.com
Page 2
Absolute Maximum Ratings (Note 1)
Infrared or Convection (20 sec) 235˚C
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
ESD Tolerance (Note 2)
Machine Model 200V
Human Body Model 2000V
±
Differential Input Voltage
Supply Voltage (V
+–V−
Output Short Circuit to V
Output Short Circuit to V
) 5.5V
+
(Note 3)
−
(Note 3)
Supply Voltage
Storage Temperature Range −65˚C to 150˚C
Junction Temperature (Note 4) 150˚C
Operating Ratings (Note 1)
Supply Voltage Range 1.8V to 5.0V
Temperature Range −40˚C to 125˚C
Thermal Resistance (θ
SC70-5 414˚C/W
SOT23-5 265˚C/W
MSOP-8 235˚C/W
SOIC-8 175˚C/W
TSSOP-14 155˚C/W
SOIC-14 127˚C/W
)
JA
Mounting Temp.
1.8V DC Electrical Characteristics
LMV931 Single / LMV932 Dual / LMV934 Quad
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 1.8V, V−= 0V, VCM=V+/2, VO=V+/2 and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Condition Min
(Note 6)
V
OS
Input Offset Voltage LMV931 (Single) 1 4
LMV932 (Dual)
LMV934 (Quad)
TCV
Input Offset Voltage Average
OS
Drift
I
B
I
OS
I
S
CMRR Common Mode Rejection
PSRR Power Supply Rejection
CMVR Input Common-Mode Voltage
Input Bias Current 15 35
Input Offset Current 13 25
Supply Current (per channel) 103 185
60
55
55
50
50 72
70
V
Ratio
Ratio
Range
LMV931, 0 ≤ V
1.4V ≤ V
CM
≤ 0.6V
CM
≤ 1.8V (Note 8)
LMV932 and LMV934
0 ≤ VCM≤ 0.6V
1.4V ≤ V
−0.2V ≤ V
1.8V ≤ V
1.8V ≤ V
For CMRR
Range ≥ 50dB
≤ 1.8V (Note 8)
CM
≤ 0V
CM
≤ 2.0V
CM
+
≤ 5V 75
T
A
T
A
= 25˚C V−−0.2 −0.2 to 2.1 V++0.2
−40˚C to
85˚C
TA= 125˚C V−+0.2 V+−0.2
A
V
Large Signal Voltage Gain
LMV931 (Single)
Large Signal Voltage Gain
LMV932 (Dual)
LMV934 (Quad)
RL= 600Ω to 0.9V,
= 0.2V to 1.6V, VCM= 0.5V
V
O
R
=2kΩ to 0.9V,
L
= 0.2V to 1.6V, VCM= 0.5V
V
O
= 600Ω to 0.9V,
R
L
= 0.2V to 1.6V, VCM= 0.5V
V
O
R
=2kΩ to 0.9V,
L
= 0.2V to 1.6V, VCM= 0.5V
V
O
77
73
80
75
75
72
78
75
−
Typ
(Note 5)
1 5.5
5.5 µV/˚C
78
76
100 dB
101
105
90
100
Max
(Note 6)
6
7.5
50
40
205
+
V
Units
mV
mV
nA
nA
µA
dB
V
dB
dB
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Page 3
1.8V DC Electrical Characteristics (Continued)
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 1.8V, V−= 0V, VCM=V+/2, VO=V+/2 and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Condition Min
(Note 6)
V
O
Output Swing RL= 600Ω to 0.9V
=±100mV
V
IN
1.65
1.63
Typ
(Note 5)
1.72
Max
(Note 6)
Units
0.077 0.105
R
=2kΩ to 0.9V
L
=±100mV
V
IN
1.75
1.74
0.120
1.77
V
0.024 0.035
0.04
I
O
Output Short Circuit Current Sourcing, VO=0V
= 100mV
V
IN
Sinking, V
= −100mV
V
IN
= 1.8V
O
4
3.3
7
5
8
9
mA
1.8V AC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 1.8V, V−= 0V, VCM=V+/2, VO=V+/2 and R
Boldface limits apply at the temperature extremes. See (Note 10)
Symbol Parameter Conditions Min
(Note 6)
Typ
(Note 5)
Max
(Note 6)
SR Slew Rate (Note 7) 0.35 V/µs
GBW Gain-Bandwidth Product 1.4 MHz
Φ
m
G
m
e
n
Phase Margin 67 deg
Gain Margin 7dB
Input-Referred Voltage Noise f = 1kHz, VCM= 0.5V 60
>
1MΩ.
L
Units
LMV931 Single / LMV932 Dual / LMV934 Quad
i
n
THD Total Harmonic Distortion f = 1kHz, AV=+1
Input-Referred Current Noise f = 1kHz 0.06
0.023 %
= 600Ω,VIN=1V
R
L
PP
Amp-to-Amp Isolation (Note 9) 123 dB
2.7V DC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 2.7V, V−= 0V, VCM=V+/2, VO=V+/2 and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Condition Min
(Note 6)
V
OS
Input Offset Voltage LMV931 (Single) 1 4
LMV932 (Dual)
LMV934 (Quad)
TCV
Input Offset Voltage Average
OS
Drift
I
B
I
OS
I
S
Input Bias Current 15 35
Input Offset Current 8 25
Supply Current (per channel) 105 190
Typ
(Note 5)
(Note 6)
1 5.5
5.5 µV/˚C
Max
6
7.5
50
40
210
Units
mV
mV
nA
nA
µA
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Page 4
2.7V DC Electrical Characteristics (Continued)
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 2.7V, V−= 0V, VCM=V+/2, VO=V+/2 and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Condition Min
CMRR Common Mode Rejection
Ratio
LMV931, 0 ≤ V
2.3V ≤ V
CM
≤ 1.5V
CM
≤ 2.7V (Note 8)
LMV932 and LMV934
CM
≤ 1.5V
CM
CM
CM
+
= 0.5V
CM
≤ 5V
≤ 2.7V (Note 8)
≤ 0V
≤ 2.9V
TA= 25˚C V−−0.2 −0.2 to 3.0 V++0.2
T
= −40˚C to
A
85˚C
PSRR Power Supply Rejection
Ratio
V
CM
Input Common-Mode Voltage
Range
LMV931 Single / LMV932 Dual / LMV934 Quad
0 ≤ V
2.3V ≤ V
−0.2V ≤ V
2.7V ≤ V
1.8V ≤ V
V
For CMRR
Range ≥ 50dB
TA= 125˚C V−+0.2 V+−0.2
A
V
V
O
I
O
Large Signal Voltage Gain
LMV931 (Single)
Large Signal Voltage Gain
LMV932 (Dual)
LMV934 (Quad)
RL= 600Ω to 1.35V,
= 0.2V to 2.5V
V
O
R
=2kΩ to 1.35V,
L
= 0.2V to 2.5V
V
O
= 600Ω to 1.35V,
R
L
= 0.2V to 2.5V
V
O
R
=2kΩ to 1.35V,
L
= 0.2V to 2.5V
V
O
Output Swing RL= 600Ω to 1.35V
=±100mV
V
IN
R
=2kΩ to 1.35V
L
=±100mV
V
IN
Output Short Circuit Current Sourcing, VO=0V
= 100mV
V
IN
Sinking, V
= −100mV
V
IN
O
=0V
(Note 6)
60
55
55
50
50 74
75
70
−
V
87
86
92
91
78
75
81
78
2.55
2.53
2.65
2.64
20
15
18
12
Typ
(Note 5)
81
80
100 dB
104
110
90
100
2.62
0.083 0.110
2.675
0.025 0.04
30
25
Max
(Note 6)
+
V
0.130
0.045
Units
dB
V
dB
dB
V
mA
2.7V AC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 2.7V, V−= 0V, VCM= 1.0V, VO= 1.35V and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Conditions Min
(Note 6)
SR Slew Rate (Note 7) 0.4 V/µs
GBW Gain-Bandwidth Product 1.4 MHz
Φ
m
G
m
e
n
i
n
www.national.com 4
Phase Margin 70 deg
Gain Margin 7.5 dB
Input-Referred Voltage Noise f = 1kHz, VCM= 0.5V 57
Input-Referred Current Noise f = 1kHz 0.082
Typ
(Note 5)
Max
(Note 6)
Units
Page 5
2.7V AC Electrical Characteristics (Continued)
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 2.7V, V−= 0V, VCM= 1.0V, VO= 1.35V and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Conditions Min
(Note 6)
THD Total Harmonic Distortion f = 1kHz, A
= 600kΩ,VIN=1V
R
L
V
=+1
PP
Typ
(Note 5)
(Note 6)
0.022 %
Amp-to-Amp Isolation (Note 9) 123 dB
5V DC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 5V, V−= 0V, VCM=V+/2, VO=V+/2 and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Condition Min
(Note 6)
V
OS
Input Offset Voltage LMV931 (Single) 1 4
LMV932 (Dual)
LMV934 (Quad)
TCV
Input Offset Voltage Average
OS
Drift
I
B
I
OS
I
S
CMRR Common Mode Rejection
PSRR Power Supply Rejection
CMVR Input Common-Mode Voltage
Input Bias Current 14 35
Input Offset Current 9 25
Supply Current (per channel) 116 210
60
55
50 78
75
70
V
Ratio
Ratio
Range
0 ≤ VCM≤ 3.8V
4.6V ≤ V
−0.2V ≤ V
5.0V ≤ V
1.8V ≤ V
V
CM
CM
CM
+
= 0.5V
CM
≤ 5V
≤ 5.0V (Note 8)
≤ 5.2V
For CMRR
Range ≥ 50dB
≤ 0V
T
= 25˚C V−−0.2 −0.2 to 5.3 V++0.2
A
T
= −40˚C to
A
85˚C
TA= 125˚C V−+0.3 V+−0.3
A
V
V
O
Large Signal Voltage Gain
LMV931 (Single)
Large Signal Voltage Gain
LMV932 (Dual)
LMV934 (Quad)
RL= 600Ω to 2.5V,
= 0.2V to 4.8V
V
O
R
=2kΩ to 2.5V,
L
= 0.2V to 4.8V
V
O
= 600Ω to 2.5V,
R
L
= 0.2V to 4.8V
V
O
R
=2kΩ to 2.5V,
L
= 0.2V to 4.8V
V
O
Output Swing RL= 600Ω to 2.5V
=±100mV
V
IN
R
=2kΩ to 2.5V
L
=±100mV
V
IN
88
87
94
93
81
78
85
82
4.855
4.835
4.945
4.935
−
Typ
(Note 5)
(Note 6)
1 5.5
5.5 µV/˚C
86
100 dB
102
113
90
100
4.890
0.120 0.160
0.180
4.967
0.037 0.065
0.075
Max
Max
6
7.5
50
40
230
V
LMV931 Single / LMV932 Dual / LMV934 Quad
Units
Units
mV
mV
nA
nA
µA
dB
+
V
dB
dB
V
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Page 6
5V DC Electrical Characteristics (Continued)
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 5V, V−= 0V, VCM=V+/2, VO=V+/2 and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Condition Min
(Note 6)
I
O
Output Short Circuit Current LMV931, Sourcing, VO=0V
= 100mV
V
IN
Sinking, V
= −100mV
V
IN
O
=5V
80
68
58
45
Typ
(Note 5)
100
65
Max
(Note 6)
5V AC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C. V+= 5V, V−= 0V, VCM=V+/2, VO= 2.5V and
>
1MΩ. Boldface limits apply at the temperature extremes. See (Note 10)
R
L
Symbol Parameter Conditions Min
(Note 6)
SR Slew Rate (Note 7) 0.42 V/µs
GBW Gain-Bandwidth Product 1.5 MHz
LMV931 Single / LMV932 Dual / LMV934 Quad
Φ
m
G
m
e
n
Phase Margin 71 deg
Gain Margin 8dB
Input-Referred Voltage Noise f = 1kHz, VCM=1V 50
Typ
(Note 5)
Max
(Note 6)
Units
mA
Units
i
n
THD Total Harmonic Distortion f = 1kHz, AV=+1
Input-Referred Current Noise f = 1kHz 0.07
0.022 %
= 600Ω,VO=1V
R
L
PP
Amp-to-Amp Isolation (Note 9) 123 dB
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.
Note 2: Human body model, 1.5kΩ in series with 100pF. Machine model, 200Ω in series with 100pF.
Note 3: Applies to both single-supply and split-supply operation. Continuous short circuit operation at elevated ambient temperature can result in exceeding the
maximum allowed junction temperature of 150˚C. Output currents in excess of 45mA over long term may adversely affect reliability.
Note 4: The maximum power dissipation is a function of T
P
=(T
D
J(MAX)–TA
Note 5: Typical Values represent the most likely parametric norm.
Note 6: All limits are guaranteed by testing or statistical analysis.
Note 7: V
Note 8: For guaranteed temperature ranges, see Input Common-Mode Voltage Range specifications.
Note 9: Input referred, V
Note 10: Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating
of the device such that T
See Applications section for information of temperature derating of the device. Absolute Maximum Ratings indicated junction temperature limits beyond which the
device may be permanently degraded, either mechanically or electrically.
)/θJA. All numbers apply for packages soldered directly into a PC board.
+
= 5V. Connected as voltage follower with 5V step input. Number specified is the slower of the positive and negative slew rates.
+
= 5V and RL= 100kΩ connected to 2.5V. Each amp excited in turn with 1kHz to produce VO=3VPP.
. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where T
J=TA
, θJA, and TA. The maximum allowable power dissipation at any ambient temperature is
J(MAX)
>
TA.
J
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Page 7
Connection Diagrams
LMV931 Single / LMV932 Dual / LMV934 Quad
5-Pin SC70-5/SOT23-5
(LMV931)
200326AO
8-Pin MSOP/SOIC
(LMV932)
14-Pin TSSOP/SOIC
(LMV934)
Top View
Top View
200326G12
Top View
Ordering Information
Package Part Number Packaging Marking Transport Media NSC
5-Pin SC70
5-Pin SOT23
8-Pin MSOP
8-Pin SOIC
14-Pin TSSOP
14-Pin SOIC
LMV931MG
LMV931MGX 3k Units Tape and Reel
LMV931MF
LMV931MFX 3k Units Tape and Reel
LMV932MM
LMV932MMX 3.5k Units Tape and Reel
LMV932MA
LMV932MAX 2.5k Units Tape and Reel
LMV934MT
LMV934MTX 2.5k Units Tape and Reel
LMV934MA
LMV934MAX 2.5k Units Tape and Reel
A74
A79A
A86A
LMV932MA
LMV934MT
LMV934MA
1k Units Tape and Reel
1k Units Tape and Reel
1k Units Tape and Reel
Rails
Rails
Rails
200326G13
Drawing
MAA05A
MF05A
MUA08A
M08A
MTC14
M14A
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Page 8
Typical Performance Characteristics Unless otherwise specified, V
= 25˚C.
T
A
= +5V, single supply,
S
Supply Current vs. Supply Voltage (LMV931) Sourcing Current vs. Output Voltage
LMV931 Single / LMV932 Dual / LMV934 Quad
20032622
Sinking Current vs. Output Voltage Output Voltage Swing vs. Supply Voltage
20032628 20032649
Output Voltage Swing vs. Supply Voltage Gain and Phase vs. Frequency
20032625
20032650 200326G8
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Page 9
LMV931 Single / LMV932 Dual / LMV934 Quad
Typical Performance Characteristics Unless otherwise specified, V
= 25˚C. (Continued)
T
A
Gain and Phase vs. Frequency Gain and Phase vs. Frequency
200326G9 200326G10
Gain and Phase vs. Frequency CMRR vs. Frequency
= +5V, single supply,
S
200326G11
PSRR vs. Frequency Input Voltage Noise vs. Frequency
20032656
20032639
20032658
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Page 10
Typical Performance Characteristics Unless otherwise specified, V
= 25˚C. (Continued)
T
A
Input Current Noise vs. Frequency THD vs. Frequency
LMV931 Single / LMV932 Dual / LMV934 Quad
20032666
THD vs. Frequency Slew Rate vs. Supply Voltage
= +5V, single supply,
S
20032667
20032668
Small Signal Non-Inverting Response Small Signal Non-Inverting Response
20032670 20032671
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20032669
Page 11
LMV931 Single / LMV932 Dual / LMV934 Quad
Typical Performance Characteristics Unless otherwise specified, V
= 25˚C. (Continued)
T
A
Small Signal Non-Inverting Response Large Signal Non-Inverting Response
20032672
Large Signal Non-Inverting Response Large Signal Non-Inverting Response
= +5V, single supply,
S
20032673
20032674 20032675
Short Circuit Current vs. Temperature (Sinking) Short Circuit Current vs. Temperature (Sourcing)
20032676
20032677
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Page 12
Typical Performance Characteristics Unless otherwise specified, V
= 25˚C. (Continued)
T
A
Offset Voltage vs. Common Mode Range Offset Voltage vs. Common Mode Range
LMV931 Single / LMV932 Dual / LMV934 Quad
20032636 20032637
Offset Voltage vs. Common Mode Range
= +5V, single supply,
S
20032638
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Page 13
Application Note
1.0 INPUT AND OUTPUT STAGE
The rail-to-rail input stage of this family provides more flexibility for the designer. The LMV931/LMV932/LMV934 use a
complimentary PNP and NPN input stage in which the PNP
stage senses common mode voltage near V
stage senses common mode voltage near V
from the PNP stage to NPN stage occurs 1V below V
both input stages have their own offset voltage, the offset of
the amplifier becomes a function of the input common mode
voltage and has a crossover point at 1V below V
This V
crossover point can create problems for both DC
OS
and AC coupled signals if proper care is not taken. Large
input signals that include the V
crossover point will cause
OS
distortion in the output signal. One way to avoid such distortion is to keep the signal away from the crossover. For
example, in a unity gain buffer configuration and with V
5V, a 5V peak-to-peak signal will contain input-crossover
distortion while a 3V peak-to-peak signal centered at 1.5V
will not contain input-crossover distortion as it avoids the
crossover point. Another way to avoid large signal distortion
is to use a gain of −1 circuit which avoids any voltage
excursions at the input terminals of the amplifier. In that
circuit, the common mode DC voltage can be set at a level
away from the V
transition in V
cross-over point. For small signals, this
OS
shows up as a VCMdependent spurious
OS
signal in series with the input signal and can effectively
degrade small signal parameters such as gain and common
mode rejection ratio. To resolve this problem, the small
signal should be placed such that it avoids the V
over point. In addition to the rail-to-rail performance, the
output stage can provide enough output current to drive
600Ω loads. Because of the high current capability, care
should be taken not to exceed the 150˚C maximum junction
temperature specification.
2.0 INPUT BIAS CURRENT CONSIDERATION
The LMV931/LMV932/LMV934 family has a complementary
bipolar input stage. The typical input bias current (I
15nA. The input bias current can develop a significant offset
voltage. This offset is primarily due to I
negative feedback resistor, R
is 100kΩ, then an offset voltage of 5mV will develop
and R
F
(V
OS=IBxRF
). Using a compensation resistor (RC), as
. For example, if IBis 50nA
F
shown in Figure 1, cancels this effect. But the input offset
current (I
) will still contribute to an offset voltage in the
OS
same manner.
−
and the NPN
+
. The transition
+
. Since
+
.
cross-
OS
flowing through the
B
S
)is
B
LMV931 Single / LMV932 Dual / LMV934 Quad
=
20032659
FIGURE 1. Canceling the Offset Voltage due to Input
Bias Current
Typical Applications
3.0 HIGH SIDE CURRENT SENSING
The high side current sensing circuit (Figure 2) is commonly
used in a battery charger to monitor charging current to
prevent over charging. A sense resistor R
to the battery directly. This system requires an op amp with
rail-to-rail input. The LMV931/LMV932/LMV934 are ideal for
this application because its common mode input range goes
up to the rail.
SENSE
is connected
FIGURE 2. High Side Current Sensing
200326H0
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Page 14
Typical Applications (Continued)
4.0 HALF-WAVE RECTIFIER WITH RAIL-TO-GROUND OUTPUT SWING
Since the LMV931/LMV932/LMV934 input common mode
range includes both positive and negative supply rails and
the output can also swing to either supply, achieving halfwave rectifier functions in either direction is an easy task. All
that is needed are two external resistors; there is no need for
diodes or matched resistors. The half wave rectifier can have
either positive or negative going outputs, depending on the
way the circuit is arranged.
In Figure 3 the circuit is referenced to ground, while in Figure
4 the circuit is biased to the positive supply. These configurations implement the half wave rectifier since the LMV931/
LMV932/LMV934 can not respond to one-half of the incoming waveform. It can not respond to one-half of the incoming
because the amplifier can not swing the output beyond either
rail therefore the output disengages during this half cycle.
During the other half cycle, however, the amplifier achieves a
half wave that can have a peak equal to the total supply
voltage. R
should be large enough not to load the
I
LMV931/LMV932/LMV934.
LMV931 Single / LMV932 Dual / LMV934 Quad
200326C3
FIGURE 3. Half-Wave Rectifier with Rail-To-Ground Output Swing Referenced to Ground
200326C0
FIGURE 4. Half-Wave Rectifier with Negative-Going Output Referenced to V
5.0 INSTRUMENTATION AMPLIFIER WITH RAIL-TO-RAIL INPUT AND OUTPUT
Some manufactures make a non-“rail-to-rail”-op amp rail-torail by using a resistive divider on the inputs. The resistors
divide the input voltage to get a rail-to-rail input range. The
problem with this method is that it also divides the signal, so
in order to get the obtained gain, the amplifier must have a
higher closed loop gain. This raises the noise and drift by the
internal gain factor and lowers the input impedance. Any
mismatch in these precision resistors reduces the CMRR as
well. The LMV981/LMV982 is rail-to-rail and therefore
doesn’t have these disadvantages.
Using three of the LMV981/LMV982 amplifiers, an instrumentation amplifier with rail-to-rail inputs and outputs can be
made as shown in Figure 5.
In this example, amplifiers on the left side act as buffers to
the differential stage. These buffers assure that the input
impedance is very high and require no precision matched
resistors in the input stage. They also assure that the difference amp is driven from a voltage source. This is necessary
to maintain the CMRR set by the matching R
The gain is set by the ratio of R
2/R1
and R4equal R2. With both rail-to-rail input and output
ranges, the input and output are only limited by the supply
1-R2
and R3should equal R
with R3-R4.
200326C4
200326C2
200326C1
200326B9
CC
voltages. Remember that even with rail-to-rail outputs, the
output can not swing past the supplies so the combined
common mode voltages plus the signal should not be
greater that the supplies or limiting will occur. For additional
applications, see National Semiconductor application notes
AN–29, AN–31, AN– 71, and AN– 127.
200326G4
1
FIGURE 5. Rail-to-rail Instrumentation Amplifier
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Page 15
Simplified Schematic
LMV931 Single / LMV932 Dual / LMV934 Quad
200326A9
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Page 16
Physical Dimensions inches (millimeters)
unless otherwise noted
LMV931 Single / LMV932 Dual / LMV934 Quad
5-Pin SC70
NS Package Number MAA05A
5-Pin SOT23
NS Package Number MF05A
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Page 17
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
LMV931 Single / LMV932 Dual / LMV934 Quad
8-Pin MSOP
NS Package Number MUA08A
8-Pin SOIC
NS Package Number M08A
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Page 18
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
LMV931 Single / LMV932 Dual / LMV934 Quad
14-Pin TSSOP
NS Package Number MTC14
14-Pin SOIC
NS Package Number M14A
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Page 19
Notes
LMV931 Single / LMV932 Dual / LMV934 Quad 1.8V, RRIO Operational Amplifiers
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
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whose failure to perform when properly used in
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support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
labeling, can be reasonably expected to result in a
significant injury to the user.
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Americas
Email: support@nsc.com
www.national.com
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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