The LMP201X is a new precision amplifier family that offers
unprecedented accuracy and stability at an affordable price
and is offered in miniature packages. This device utilizes
patented techniques to measure and continually correct the
input offset error voltage. The result is an amplifier which is
ultra stable over time and temperature. It has excellent
CMRR and PSRR ratings, and does not exhibit the familiar
1/f voltage and current noise increase that plagues traditional amplifiers. The combination of the LMP201X characteristics makes it a good choice for transducer amplifiers,
high gain configurations, ADC buffer amplifiers, DAC I-V
conversion, and any other 2.7V-5V application requiring precision and long term stability.
Other useful benefits of the LMP201X are rail-to-rail output,
a low supply current of 930 µA, and wide gain-bandwidth
product of 3 MHz. These extremely versatile features found
in the LMP201X provide high performance and ease of use.
Connection Diagrams
5-Pin SOT238-Pin MSOP/SOIC
Features
(For VS= 5V, Typical unless otherwise noted)
n Low guaranteed V
n Low noise with no 1/f35nV/
n High CMRR130 dB
n High PSRR120 dB
n High A
n Wide gain-bandwidth product3MHz
n High slew rate4V/µs
n Low supply current930µA
n Rail-to-rail output30mV
n No external capacitors required
VOL
over temperature60 µV
OS
130 dB
Applications
n Precision instrumentation amplifiers
n Thermocouple amplifiers
n Strain gauge bridge amplifier
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
ESD Tolerance
Human Body Model2000V
Machine Model200V
Supply Voltage5.8V
Common-Mode Input
Voltage−0.3 ≤ V
Lead Temperature
(soldering 10 sec.)+300˚C
≤ VCC+0.3V
CM
Operating Ratings (Note 1)
Supply Voltage2.7V to 5.25V
Storage Temperature Range−65˚C to 150˚C
Operating Temperature Range
LMP2011MF, LMP2011MFX−40˚C to 125˚C
LMP2011MA, LPM2011MAX−40˚C to 125˚C
LMP2012MM, LMP2011MMX−40˚C to 125˚C
LMP2014SD, LMP2014SDX−40˚C to 125˚C
LMP2014MT, LMP2014MTX−40˚C to 85˚C
2.7V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T
+
= 2.7V, V-= 0V, VCM= 1.35V, VO= 1.35V and R
V
SymbolParameterConditions
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
V
OS
Input Offset Voltage0.825
>
1MΩ. Boldface limits apply at the temperature extremes.
L
Min
(Note 3)
Typ
(Note 2)
Offset Calibration Time0.510
TCV
Input Offset Voltage0.015µV/˚C
OS
Long-Term Offset Drift0.006µV/month
Lifetime V
I
IN
I
OS
R
IND
Input Current-3pA
Input Offset Current6pA
Input Differential Resistance9MΩ
CMRRCommon Mode Rejection
Ratio
Drift2.5µV
OS
−0.3 ≤ V
0 ≤ V
CM
≤ 0.9V
CM
≤ 0.9V
13095
PSRRPower Supply Rejection Ratio12095
A
VOL
V
O
Open Loop Voltage GainRL=10kΩ13095
=2kΩ12490
R
L
Output SwingRL=10kΩ to 1.35V
(diff) =±0.5V
V
IN
2.665
2.655
2.68
0.0330.060
R
=2kΩ to 1.35V
L
(diff) =±0.5V
V
IN
2.630
2.615
2.65
0.0610.085
I
O
R
OUT
I
S
Output CurrentSourcing, VO=0V
(diff) =±0.5V
V
IN
Sinking, V
(diff) =±0.5V
V
IN
O
=5V
Output ImpedanceΩ
Supply Current per Channel0.9191.20
125
185
= 25˚C,
J
Max
(Note 3)Units
µV
60
ms
12
dB
90
dB
90
90
dB
85
V
0.075
V
0.105
3
mA
3
mA
1.50
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LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
2.7V AC Electrical CharacteristicsT
>
1MΩ. Boldface limits apply at the temperature extremes.
SymbolParameterConditions
= 25˚C, V+= 2.7V, V-= 0V, VCM= 1.35V, VO= 1.35V, and R
J
Min
(Note 3)
Typ
(Note 2)
Max
(Note 3)Units
GBWGain-Bandwidth Product3MHz
SRSlew Rate4V/µs
θ
m
G
m
e
n
i
n
Phase Margin60Deg
Gain Margin−14dB
Input-Referred Voltage Noise35nV/
Input-Referred Current NoisepA/
enp-pInput-Referred Voltage NoiseRS= 100Ω,DCto10Hz850nV
t
rec
t
S
Input Overload Recovery Time50ms
Output Settling timeAV= +1, RL=2kΩ
1V Step
= −1, RL=2kΩ
A
V
1V Step
1%
0.1%
0.01%
1%
0.1%
ns
0.01%
5V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T
-
= 0V, VCM= 2.5V, VO= 2.5V and R
5V, V
SymbolParameterConditions
V
OS
Input Offset Voltage0.1225
>
1MΩ. Boldface limits apply at the temperature extremes.
L
Min
(Note 3)
(Note 2)
Typ
= 25˚C, V+=
J
Max
(Note 3)Units
µV
60
Offset Calibration Time0.510
ms
12
TCV
Input Offset Voltage0.015µV/˚C
OS
Long-Term Offset Drift0.006µV/month
Lifetime V
I
IN
I
OS
R
IND
Input Current-3pA
Input Offset Current6pA
Input Differential Resistance9MΩ
CMRRCommon Mode Rejection
Ratio
PSRRPower Supply Rejection Ratio12095
Drift2.5µV
OS
−0.3 ≤ V
0 ≤ V
CM
CM
≤ 3.2
≤ 3.2
130100
90
dB
dB
90
A
VOL
Open Loop Voltage GainRL=10kΩ130105
100
RL=2kΩ13295
dB
90
V
O
Output SwingRL=10kΩ to 2.5V
(diff) =±0.5V
V
IN
4.96
4.95
4.978
0.0400.070
V
0.085
R
=2kΩ to 2.5V
L
(diff) =±0.5V
V
IN
4.895
4.875
4.919
0.0910.115
V
0.140
L
pp
www.national.com3
5V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T
-
= 0V, VCM= 2.5V, VO= 2.5V and R
5V, V
>
1MΩ. Boldface limits apply at the temperature extremes. (Continued)
L
= 25˚C, V+=
J
SymbolParameterConditions
I
O
R
OUT
I
S
Output CurrentSourcing, VO=0V
(diff) =±0.5V
V
IN
Sinking, V
(diff) =±0.5V
V
IN
O
=5V
Output ImpedanceΩ
Supply Current per Channel0.9301.20
Min
(Note 3)
Typ
(Note 2)
158
178
Max
(Note 3)Units
6
6
1.50
5V AC Electrical Characteristics T
= 25˚C, V+= 5V, V-= 0V, VCM= 2.5V, VO= 2.5V, and R
J
1MΩ. Boldface limits apply at the temperature extremes.
Min
SymbolParameterConditions
GBWGain-Bandwidth Product3MHz
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
(Note 3)
Typ
(Note 2)
Max
(Note 3)Units
SRSlew Rate4V/µs
θ
m
G
m
e
n
i
n
Phase Margin60deg
Gain Margin−15dB
Input-Referred Voltage Noise35nV/
Input-Referred Current NoisepA/
enp-pInput-Referred Voltage NoiseRS= 100Ω,DCto10Hz850nV
t
rec
t
S
Input Overload Recovery Time50ms
Output Settling timeAV= +1, RL=2kΩ
1V Step
1%
0.1%
0.01%
= −1, RL=2kΩ
A
V
1V Step
1%
0.1%
0.01%
Note 1: Absolute Maximum Ratings indicate limits beyond which damage 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 test conditions, see the Electrical Characteristics.
Note 2: Typical values represent the most likely parametric norm.
Note 3: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlations using statistical quality control
(SQC) method.
mA
mA
>
L
pp
ns
Ordering Information
PackagePart NumberTemperature
Range
5-Pin
SOT23
8-Pin
MSOP
8-Pin
SOIC
14-Pin
LLP
14-Pin
TSSOP
www.national.com4
LMP2011MF
LMP2011MFX3k Units Tape and Reel
LMP2012MM
LMP2012MMX3.5k Units Tape and Reel
−40˚C to 125˚C
LMP2011MA
LMP2011MAX2.5k Units Tape and Reel
LMP2014SD
LMP2014SDX2.5 Units Tape and Reel
LMP2014MT
LMP2014MTX2.5k Units Tape and Reel
−40˚C to 125˚CP2014SD
−40˚C to 85˚CLMP2014MT
Package MarkingTransport MediaNSC Drawing
LMP2011MA
AN1A
AP1A
1k Units Tape and Reel
1k Units Tape and Reel
95 Units/Rail
250 Units Tape and Reel
94 Units/Rail
MF05A
MUA08A
M08A
SRC14A
MTC14
Typical Performance Characteristics
TA=25C, VS= 5V unless otherwise specified.
Supply Current vs. Supply VoltageOffset Voltage vs. Supply Voltage
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
20071524
Offset Voltage vs. Common ModeOffset Voltage vs. Common Mode
2007153520071534
Voltage Noise vs. FrequencyInput Bias Current vs. Common Mode
20071525
20071504
20071503
www.national.com5
Typical Performance Characteristics (Continued)
PSRR vs. FrequencyPSRR vs. Frequency
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
2007150720071506
Output Sourcing@2.7VOutput Sourcing@5V
20071526
Output Sinking@2.7VOutput Sinking@5V
20071527
2007152820071529
www.national.com6
Typical Performance Characteristics (Continued)
Max Output Swing vs. Supply VoltageMax Output Swing vs. Supply Voltage
2007153020071531
Min Output Swing vs. Supply VoltageMin Output Swing vs. Supply Voltage
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
2007153220071533
CMRR vs. FrequencyOpen Loop Gain and Phase vs. Supply Voltage
20071505
20071508
www.national.com7
Typical Performance Characteristics (Continued)
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
Open Loop Gain and Phase vs. R
Open Loop Gain and Phase vs. C
@
2.7VOpen Loop Gain and Phase vs. R
L
2007150920071510
@
2.7VOpen Loop Gain and Phase vs. C
L
@
5V
L
@
5V
L
20071511
20071512
Open Loop Gain and Phase vs. Temperature@2.7VOpen Loop Gain and Phase vs. Temperature@5V
2007153620071537
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Typical Performance Characteristics (Continued)
THD+N vs. AMPLTHD+N vs. Frequency
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
0.1 Hz − 10 Hz Noise vs. Time
20071514
20071515
20071513
www.national.com9
Application Information
THE BENEFITS OF LMP201X
NO 1/f NOISE
Using patented methods, the LMP201X eliminates the 1/f
noise present in other amplifiers. That noise, which increases as frequency decreases, is a major source of measurement error in all DC-coupled measurements. Lowfrequency noise appears as a constantly-changing signal in
series with any measurement being made. As a result, even
when the measurement is made rapidly, this constantlychanging noise signal will corrupt the result. The value of this
noise signal can be surprisingly large. For example: If a
conventional amplifier has a flat-band noise level of 10nV/
and a noise corner of 10 Hz, the RMS noise at 0.001
Hz is 1µV/
peak error, in the frequency range 0.001 Hz to 1.0 Hz. In a
circuit with a gain of 1000, this produces a 0.50 mV peakto-peak output error. This number of 0.001 Hz might appear
unreasonably low, but when a data acquisition system is
operating for 17 minutes, it has been on long enough to
include this error. In this same time, the LMP201X will only
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
have a 0.21 mV output error. This is smaller by 2.4 x. Keep
in mind that this 1/f error gets even larger at lower frequencies. At the extreme, many people try to reduce this error by
integrating or taking several samples of the same signal.
This is also doomed to failure because the 1/f nature of this
noise means that taking longer samples just moves the
measurement into lower frequencies where the noise level is
even higher.
The LMP201X eliminates this source of error. The noise
level is constant with frequency so that reducing the bandwidth reduces the errors caused by noise.
Another source of error that is rarely mentioned is the error
voltage caused by the inadvertent thermocouples created
when the common "Kovar type" IC package lead materials
are soldered to a copper printed circuit board. These steelbased leadframe materials can produce over 35 µV/˚C when
soldered onto a copper trace. This can result in thermocouple noise that is equal to the LMP201X noise when there
is a temperature difference of only 0.0014˚C between the
lead and the board!
For this reason, the lead-frame of the LMP201X is made of
copper. This results in equal and opposite junctions which
cancel this effect. The extremely small size of the SOT-23
package results in the leads being very close together. This
further reduces the probability of temperature differences
and hence decreases thermal noise.
OVERLOAD RECOVERY
The LMP201X recovers from input overload much faster
than most chopper-stabilized op amps. Recovery from driving the amplifier to 2X the full scale output, only requires
about 40 ms. Many chopper-stabilized amplifiers will take
from 250 ms to several seconds to recover from this same
overload. This is because large capacitors are used to store
the unadjusted offset voltage.
. This is equivalent to a 0.50 µV peak-to-
20071516
FIGURE 1.
The wide bandwidth of the LMP201X enhances performance
when it is used as an amplifier to drive loads that inject
transients back into the output. ADCs (Analog-to-Digital Converters) and multiplexers are examples of this type of load.
To simulate this type of load, a pulse generator producing a
1V peak square wave was connected to the output through a
10 pF capacitor. (Figure 1) The typical time for the output to
recover to 1% of the applied pulse is 80 ns. To recover to
0.1% requires 860ns. This rapid recovery is due to the wide
bandwidth of the output stage and large total GBW.
NO EXTERNAL CAPACITORS REQUIRED
The LMP201X does not need external capacitors. This eliminates the problems caused by capacitor leakage and dielectric absorption, which can cause delays of several seconds
from turn-on until the amplifier’s error has settled.
MORE BENEFITS
The LMP201X offers the benefits mentioned above and
more. It has a rail-to-rail output and consumes only 950 µAof
supply current while providing excellent DC andAC electrical
performance. In DC performance, the LMP201X achieves
130 dB of CMRR, 120 dB of PSRR and 130 dB of open loop
gain. In AC performance, the LMP201X provides 3 MHz of
gain-bandwidth product and 4 V/µs of slew rate.
HOW THE LMP201X WORKS
The LMP201X uses new, patented techniques to achieve the
high DC accuracy traditionally associated with chopperstabilized amplifiers without the major drawbacks produced
by chopping. The LMP201X continuously monitors the input
offset and corrects this error. The conventional chopping
process produces many mixing products, both sums and
differences, between the chopping frequency and the incoming signal frequency. This mixing causes large amounts of
distortion, particularly when the signal frequency approaches
the chopping frequency. Even without an incoming signal,
the chopper harmonics mix with each other to produce even
more trash. If this sounds unlikely or difficult to understand,
look at the plot (Figure 2), of the output of a typical (MAX432)
chopper-stabilized op amp. This is the output when there is
no incoming signal, just the amplifier in a gain of -10 with the
input grounded. The chopper is operating at about 150 Hz;
the rest is mixing products. Add an input signal and the noise
gets much worse. Compare this plot with Figure 3 of the
LMP201X. This data was taken under the exact same conditions. The auto-zero action is visible at about 30 kHz but
note the absence of mixing products at other frequencies.As
a result, the LMP201X has very low distortion of 0.02% and
very low mixing products.
www.national.com10
Application Information (Continued)
20071517
FIGURE 2.
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
PRECISION STRAIN-GAUGE AMPLIFIER
This Strain-Gauge amplifier (Figure 4) provides high gain
(1006 or~60 dB) with very low offset and drift. Using the
resistors’ tolerances as shown, the worst case CMRR will be
greater than 108 dB. The CMRR is directly related to the
resistor mismatch. The rejection of common-mode error, at
the output, is independent of the differential gain, which is
set by R3. The CMRR is further improved, if the resistor ratio
matching is improved, by specifying tighter-tolerance resistors, or by trimming.
20071518
20071504
FIGURE 3.
INPUT CURRENTS
The LMP201X’s input currents are different than standard
bipolar or CMOS input currents in that it appears as a current
flowing in one input and out the other. Under most operating
conditions, these currents are in the picoamp level and will
have little or no effect in most circuits. These currents tend to
increase slightly when the common-mode voltage is near the
minus supply. (See the typical curves.) At high temperatures
such as 85˚C, the input currents become larger, 0.5 nA
typical, and are both positive except when the V
−
. If operation is expected at low common-mode voltages
V
CM
is near
and high temperature, do not add resistance in series with
the inputs to balance the impedances. Doing this can cause
an increase in offset voltage. A small resistance such as 1
kΩ can provide some protection against very large transients
or overloads, and will not increase the offset significantly.
FIGURE 4.
Extending Supply Voltages and Output Swing by Using
a Composite Amplifier Configuration:
In cases where substantially higher output swing is required
with higher supply voltages, arrangements like the ones
shown in Figure 5 and Figure 6 could be used. These
configurations utilize the excellent DC performance of the
LMP201X while at the same time allow the superior voltage
and frequency capabilities of the LM6171 to set the dynamic
performance of the overall amplifier. For example, it is pos-
±
sible to achieve
GBW (A
due to V
V
OS
12V output swing with 300 MHz of overall
= 100) while keeping the worst case output shift
less than 4 mV. The LMP201X output voltage is
kept at about mid-point of its overall supply voltage, and its
input common mode voltage range allows the V- terminal to
be grounded in one case (Figure 5, inverting operation) and
tied to a small non-critical negative bias in another (Figure 6,
non-inverting operation). Higher closed-loop gains are also
possible with a corresponding reduction in realizable bandwidth. Table 1 shows some other closed loop gain possibilities along with the measured performance in each case.
www.national.com11
Application Information (Continued)
LMP2011 Single/ LMP2012 Dual/ LMP2014 Quad
20071520
20071519
FIGURE 5.
TABLE 1. Composite Amplifier Measured Performance
AVR1
R2ΩC2pFBW
Ω
MHzSR(V/µs)
en p-p
(mV
)
PP
5020010k83.317837
10010010k102.517470
1001k100k0.673.117070
500200100k1.751.496250
1000100100k2.20.9864400
In terms of the measured output peak-to-peak noise, the
following relationship holds between output noise voltage, e
p-p, for different closed-loop gain, AV, settings, where −3 dB
Bandwidth is BW:
FIGURE 6.
It should be kept in mind that in order to minimize the output
noise voltage for a given closed-loop gain setting, one could
minimize the overall bandwidth. As can be seen from Equation 1 above, the output noise has a square-root relationship
to the Bandwidth.
In the case of the inverting configuration, it is also possible to
increase the input impedance of the overall amplifier, by
raising the value of R1, without having to increase the feedback resistor, R2, to impractical values, by utilizing a "Tee"
network as feedback. See the LMC6442 data sheet (Application Notes section) for more details on this.
n
FIGURE 7.
www.national.com12
20071521
Application Information (Continued)
LMP201X AS ADC INPUT AMPLIFIER
The LMP201X is a great choice for an amplifier stage immediately before the input of an ADC (Analog-to-Digital Converter), whether AC or DC coupled. See Figure 7 and Figure
8. This is because of the following important characteristics:
A) Very low offset voltage and offset voltage drift over time
and temperature allow a high closed-loop gain setting
without introducing any short-term or long-term errors.
For example, when set to a closed-loop gain of 100 as
the analog input amplifier for a 12-bit A/D converter, the
overall conversion error over full operation temperature
and 30 years life of the part (operating at 50˚C) would be
less than 5 LSBs.
B) Fast large-signal settling time to 0.01% of final value (1.4
µs) allows 12 bit accuracy at 100 KH
rate.
C) No flicker (1/f) noise means unsurpassed data accuracy
over any measurement period of time, no matter how
long. Consider the following op amp performance, based
on a typical low-noise, high-performance commerciallyavailable device, for comparison:
Op amp flatband noise = 8nV/
or more sampling
Z
1/f corner frequency = 100 Hz
= 2000
A
V
Measurement time = 100 sec
Bandwidth=2Hz
This example will result in about 2.2 mV
(1.9 LSB) of
PP
output noise contribution due to the op amp alone, compared to about 594 µV
(less than 0.5 LSB) when that
PP
op amp is replaced with the LMP201X which has no 1/f
contribution. If the measurement time is increased from
100 seconds to 1 hour, the improvement realized by
using the LMP201X would be a factor of about 4.8 times
(2.86 mV
compared to 596 µV when LMP201X is
PP
used) mainly because the LMP201X accuracy is not
compromised by increasing the observation time.
D) Copper leadframe construction minimizes any thermo-
couple effects which would degrade low level/high gain
data conversion application accuracy (see discussion
under "The Benefits of the LMP201X" section above).
E) Rail-to-Rail output swing maximizes the ADC dynamic
range in 5-Volt single-supply converter applications. Below are some typical block diagrams showing the
LMP201X used as an ADC amplifier (Figure 7 and Figure
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.
For the most current product information visit us at www.national.com.
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