LMC6064
Precision CMOS Quad Micropower Operational Amplifier
General Description
The LMC6064 is a precision quad low offset voltage, micropower operational amplifier, capable of precision single
supply operation. Performance characteristics include ultra
low input bias current, high voltage gain, rail-to-rail output
swing, and an input common mode voltage range that includes ground. These features, plus its low power consumption make the LMC6064 ideally suited for battery powered
applications.
Other applications using the LMC6064 include precision
full-wave rectifiers, integrators, references, sample-and-hold
circuits, and true instrumentation amplifiers.
This device is built with National’s advanced double-Poly
Silicon-Gate CMOS process.
For designs that require higher speed, see the LMC6084
precision quad operational amplifier.
For single or dual operational amplifier with similar features,
see the LMC6061 or LMC6062 respectively.
PATENT PENDING
Features
(Typical Unless Otherwise Noted)
n Low offset voltage: 100 µV
n Ultra low supply current: 16 µA/Amplifier
n Operates from 4.5V to 15V single supply
n Ultra low input bias current: 10 fA
n Output swing within 10 mV of supply rail, 100k load
n Input common-mode range includes V
−
n High voltage gain: 140 dB
n Improved latchup immunity
Applications
n Instrumentation amplifier
n Photodiode and infrared detector preamplifier
n Transducer amplifiers
n Hand-held analytic instruments
n Medical instrumentation
n D/A converter
n Charge amplifier for piezoelectric transducers
Connection Diagram
Ordering Information
Package
Temperature Range
NSC
Drawing
Transport
Media
Military Industrial
−55˚C to +125˚C −40˚C to +85˚C
14-Pin LMC6064AMN LMC6064AIN N14A Rail
Molded DIP LMC6064IN
14-Pin LMC6064AIM M14A Rail
Small Outline LMC6064IM Tape and Reel
14-Pin LMC6064AMJ J14A Rail
Ceramic DIP
14-Pin DIP/SO
DS011466-1
Top View
November 1994
LMC6064 Precision CMOS Quad Micropower Operational Amplifier
© 1999 National Semiconductor Corporation DS011466 www.national.com
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact theNationalSemiconductor Sales Office/
Distributors for availability and specifications.
Differential Input Voltage
±
Supply Voltage
Voltage at Input/Output Pin (V
+
) +0.3V,
(V
−
) −0.3V
Supply Voltage (V
+−V−
) 16V
Output Short Circuit to V
+
(Note 11)
Output Short Circuit to V
−
(Note 2)
Lead Temperature
(Soldering, 10 sec.) 260˚C
Storage Temp. Range −65˚C to +150˚C
Junction Temperature 150˚C
ESD Tolerance (Note 4) 2 kV
Current at Input Pin
±
10 mA
Current at Output Pin
±
30 mA
Current at Power Supply Pin 40 mA
Power Dissipation (Note 3)
Operating Ratings (Note 1)
Temperature Range
LMC6064AM −55˚C ≤ T
J
≤ +125˚C
LMC6064AI, LMC6064I −40˚C ≤ T
J
≤ +85˚C
Supply Voltage 4.5V ≤ V
+
≤ 15.5V
Thermal Resistance (θ
JA
) (Note 12)
14-Pin Molded DIP 81˚C/W
14-Pin SO 126˚C/W
Power Dissipation (Note 10)
DC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for T
J
=
25˚C. Boldface limits apply at the temperature extremes. V
+
=
5V,
V
−
=
0V, V
CM
=
1.5V, V
O
=
2.5V and R
L
>
1M unless otherwise specified.
Typ LMC6064AM LMC6064AI LMC6064I
Symbol Parameter Conditions (Note 5) Limit Limit Limit Units
(Note 6) (Note 6) (Note 6)
V
OS
Input Offset Voltage 100 350 350 800 µV
1200 900 1300 Max
TCV
OS
Input Offset Voltage 1.0 µV/˚C
Average Drift
I
B
Input Bias Current 0.010 pA
100 4 4 Max
I
OS
Input Offset Current 0.005 pA
100 2 2 Max
R
IN
Input Resistance
>
10 Tera Ω
CMRR Common Mode 0V ≤ V
CM
≤ 12.0V 85 75 75 66 dB
Rejection Ratio V
+
=
15V 70 72 63 Min
+PSRR Positive Power Supply 5V ≤ V
+
≤ 15V 85 75 75 66 dB
Rejection Ratio V
O
=
2.5V 70 72 63 Min
−PSRR Negative Power Supply 0V ≤ V
−
≤ −10V 100 84 84 74 dB
Rejection Ratio 70 81 71 Min
V
CM
Input Common-Mode V
+
=
5V and 15V −0.4 −0.1 −0.1 −0.1 V
Voltage Range for CMRR ≥ 60 dB 000Max
V
+
− 1.9 V+− 2.3 V+− 2.3 V+− 2.3 V
V
+
− 2.6 V+− 2.5 V+− 2.5 Min
A
V
Large Signal R
L
=
100 kΩ Sourcing 4000 400 400 300 V/mV
Voltage Gain (Note 7) 200 300 200 Min
Sinking 3000 180 180 90 V/mV
70 100 60 Min
R
L
=
25 kΩ Sourcing 3000 400 400 200 V/mV
(Note 7) 150 150 80 Min
Sinking 2000 100 100 70 V/mV
35 50 35 Min
www.national.com 2
DC Electrical Characteristics (Continued)
Unless otherwise specified, all limits guaranteed for T
J
=
25˚C. Boldface limits apply at the temperature extremes. V
+
=
5V,
V
−
=
0V, V
CM
=
1.5V, V
O
=
2.5V and R
L
>
1M unless otherwise specified.
Typ LMC6064AM LMC6064AI LMC6064I
Symbol Parameter Conditions (Note 5) Limit Limit Limit Units
(Note 6) (Note 6) (Note 6)
V
O
Output Swing V
+
=
5V 4.995 4.990 4.990 4.950 V
R
L
=
100 kΩ to 2.5V 4.970 4.980 4.925 Min
0.005 0.010 0.010 0.050 V
0.030 0.020 0.075 Max
V
+
=
5V 4.990 4.975 4.975 4.950 V
R
L
=
25 kΩ to 2.5V 4.955 4.965 4.850 Min
0.010 0.020 0.020 0.050 V
0.045 0.035 0.150 Max
V
+
=
15V 14.990 14.975 14.975 14.950 V
R
L
=
100 kΩ to 7.5V 14.955 14.965 14.925 Min
0.010 0.025 0.025 0.050 V
0.050 0.035 0.075 Max
V
+
=
15V 14.965 14.900 14.900 14.850 V
R
L
=
25 kΩ to 7.5V 14.800 14.850 14.800 Min
0.025 0.050 0.050 0.100 V
0.200 0.150 0.200 Max
I
O
Output Current Sourcing, V
O
=
0V 22 16 16 13 mA
V
+
=
5V 8108Min
Sinking, V
O
=
5V 21 16 16 16 mA
788Min
I
O
Output Current Sourcing, V
O
=
0V 25 15 15 15 mA
V
+
=
15V 91010Min
Sinking, V
O
=
13V 35 24 24 24 mA
(Note 11) 788Min
I
S
Supply Current All Four Amplifiers 64 76 76 92 µA
V
+
=
+5V, V
O
=
1.5V 120 92 112 Max
All Four Amplifiers 94 94 114 µA
V
+
=
+15V, V
O
=
7.5V 80 140 110 132 Max
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AC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for T
J
=
25˚C, Boldface limits apply at the temperature extremes. V
+
=
5V,
V
−
=
0V, V
CM
=
1.5V, V
O
=
2.5V and R
L
>
1M unless otherwise specified.
Typ LMC6064AM LMC6064AI LMC6064I
Symbol Parameter Conditions (Note 5) Limit Limit Limit Units
(Note 6) (Note 6) (Note 6)
SR Slew Rate (Note 8) 35 20 20 15 V/ms
8107Min
GBW Gain-Bandwidth Product 100 kHz
θ
m
Phase Margin 50 Deg
Amp-to-Amp Isolation (Note 9) 155 dB
e
n
Input-Referred Voltage Noise F=1 kHz 83
i
n
Input-Referred Current Noise F=1 kHz 0.0002
T.H.D. Total Harmonic Distortion F=1 kHz, A
V
=
−5
R
L
=
100 kΩ,V
O
=
2V
PP
0.01
%
±
5V Supply
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 do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed.
Note 2: Applies to both single-supply and split-supply operation. Continous short circuit operation at elevated ambient temperature can result in exceeding the maximum allowed junction temperature of 150˚C. Output currents in excess of
±
30 mA over long term may adversely affect reliability.
Note 3: The maximum power dissipation is a function of T
J(Max)
, θJA, and TA. The maximum allowable power dissipation at any ambient temperature is P
D
=
(T
J(Max)
−TA)/θJA.
Note 4: Human body model, 1.5 kΩ in series with 100 pF.
Note 5: Typical values represent the most likely parametric norm.
Note 6: All limits are guaranteed by testing or statistical analysis.
Note 7: V
+
=
15V, V
CM
=
7.5V and R
L
connected to 7.5V. For Sourcing tests, 7.5V ≤ VO≤ 11.5V. For Sinking tests, 2.5V ≤ VO≤ 7.5V.
Note 8: V
+
=
15V. Connected as Voltage Follower with 10V step input. Number specified is the slower of the positive and negative slew rates.
Note 9: Input referred V
+
=
15V and R
L
=
100 kΩ connected to 7.5V. Each amp excited in turn with 100 Hz to produce V
O
=
12 V
PP
.
Note 10: For operating at elevated temperatures the device must be derated based on the thermal resistance θ
JA
with P
D
=
(T
J–TA
)/θJA.
Note 11: Do not connect output to V
+
, when V+is greater than 13V or reliability witll be adversely affected.
Note 12: All numbers apply for packages soldered directly into a PC board.
Note 13: For guaranteed Military Temperature Range parameters see RETSMC6064X.
www.national.com 4
Typical Performance Characteristics
Distribution of LMC6064
Input Offset Voltage
(T
A
=
+25˚C)
DS011466-15
Distribution of LMC6064
Input Offset Voltage
(T
A
=
−55˚C)
DS011466-16
Distribution of LMC6064
Input Offset Voltage
(T
A
=
+125˚C)
DS011466-17
Input Bias Current
vs Temperature
DS011466-18
Supply Current
vs Supply Voltage
DS011466-19
Input Voltage
vs Output Voltage
DS011466-20
Common Mode
Rejection Ratio
vs Frequency
DS011466-21
Power Supply Rejection
Ratio vs Frequency
DS011466-22
Input Voltage Noise
vs Frequency
DS011466-23
www.national.com5
Typical Performance Characteristics (Continued)
Output Characteristics
Sourcing Current
DS011466-24
Output Characteristics
Sinking Current
DS011466-25
Gain and Phase Response
vs Temperature
(−55˚C to +125˚C)
DS011466-26
Gain and Phase
Response vs Capacitive Load
with R
L
=
20 kΩ
DS011466-27
Gain and Phase
Response vs Capacitive Load
with R
L
=
500 kΩ
DS011466-28
Open Loop
Frequency Response
DS011466-29
Inverting Small Signal
Pulse Response
DS011466-30
Inverting Large Signal
Pulse Response
DS011466-31
Non-Inverting Small
Signal Pulse Response
DS011466-32
www.national.com 6
Typical Performance Characteristics (Continued)
Applications Hints
AMPLIFIER TOPOLOGY
The LMC6064 incorporates a novel op-amp design topology
that enables it to maintain rail-to-rail output swing even when
driving a large load. Instead of relying on a push-pull unity
gain output buffer stage, the output stage is taken directly
from the internal integrator, which provides both low output
impedance and large gain. Special feed-forward compensation design techniques are incorporated to maintain stability
over a wider range of operating conditions than traditional
micropower op-amps. These features make the LMC6064
both easier to design with, and provide higher speed than
products typically found in this ultra-low power class.
COMPENSATING FOR INPUT CAPACITANCE
It is quite common to use large values of feedback resistance for amplifiers with ultra-low input current, like the
LMC6064.
Although the LMC6064 is highly stable over a wide range of
operating conditions, certain precautions must be met to
achieve the desired pulse response when a large feedback
resistor is used. Large feedback resistors and even small
values of input capacitance, due to transducers, photodiodes, and circuit board parasitics, reduce phase margins.
When high input impedances are demanded, guarding of the
LMC6064 is suggested. Guarding input lines will not only reduce leakage, but lowers stray input capacitance as well.
(See
Printed-Circuit-Board Layout for High Impedance
Work
).
The effect of input capacitance can be compensated for by
adding a capacitor. Place a capacitor, C
f
, around the feed-
back resistor (as in
Figure 1
) such that:
or
R
1CIN
≤ R2C
f
Since it is often difficult to know the exact value of CIN,Cfcan
be experimentally adjusted so that the desired pulse response is achieved. Refer to the LMC660 and the LMC662
for a more detailed discussion on compensating for input
capacitance.
Non-Inverting Large
Signal Pulse Response
DS011466-33
Crosstalk Rejection
vs Frequency
DS011466-34
Stability vs Capacitive
Load, R
L
=
20 kΩ
DS011466-35
Stability vs Capacitive
Load R
L
=
1MΩ
DS011466-36
DS011466-4
FIGURE 1. Canceling the Effect of Input Capacitance
www.national.com7
Applications Hints (Continued)
CAPACITIVE LOAD TOLERANCE
All rail-to-rail output swing operational amplifiers have voltage gain in the output stage. A compensation capacitor is
normally included in this integrator stage. The frequency location of the dominate pole is affected by the resistive load
on the amplifier. Capacitive load driving capability can be optimized by using an appropriate resistive load in parallel with
the capacitive load (see typical curves).
Direct capacitive loading will reduce the phase margin of
many op-amps.A pole in the feedback loop is created by the
combination of the op-amp’s output impedance and the capacitive load. This pole induces phase lag at the unity-gain
crossover frequency of the amplifier resulting in either an oscillatory or underdamped pulse response. With a few external components, op amps can easily indirectly drive capacitive loads, as shown in
Figure 2
.
In the circuit of
Figure 2
, R1 and C1 serve to counteract the
loss of phase margin by feeding the high frequency component of the output signal back to the amplifier’s inverting input, thereby preserving phase margin in the overall feedback
loop.
Capacitive load driving capability is enhanced by using a pull
up resistor to V
+
(
Figure 3
). Typically a pull up resistor conducting 10 µA or more will significantly improve capacitive
load responses. The value of the pull up resistor must be determined based on the currentsinking capability of the amplifier with respect to the desired output swing. Open loop gain
of the amplifier can also be affected by the pull up resistor
(see Electrical Characteristics).
PRINTED-CIRCUIT-BOARD LAYOUT
FOR HIGH-IMPEDANCE WORK
It is generally recognized that any circuit which must operate
with less than 1000 pA of leakage current requires special
layout of the PC board. When one wishes to take advantage
of the ultra-low bias current of the LMC6064, typically less
than 10 fA, it is essential to have an excellent layout. Fortunately, the techniques of obtaining low leakages are quite
simple. First, the user must not ignore the surface leakage of
the PC board, even thoughit may sometimes appear acceptably low, because under conditions of high humidity or dust
or contamination, the surface leakage will be appreciable.
To minimize the effect of any surface leakage, lay out a ring
of foil completely surrounding the LMC6064’s inputs and the
terminals of capacitors, diodes, conductors, resistors, relay
terminals etc. connected to the op-amp’s inputs, as in
Figure
4
. To have a significant effect, guard rings should be placed
on both the top and bottom of the PC board. This PC foil
must then be connected to a voltage which is at the same
voltage as the amplifier inputs, since no leakage current can
flow between two points at the same potential. For example,
a PC board trace-to-pad resistance of 10
12
Ω, which is normally considered a very large resistance, could leak 5 pA if
the trace were a 5V bus adjacent to the pad of the input. This
would cause a 100 times degradation from the LMC6064’s
actual performance. However, if a guard ring is held within
5 mV of the inputs, then even a resistance of 10
11
Ω would
cause only 0.05 pA of leakage current. See
Figure 5
for typical connections of guard rings for standard op-amp
configurations.
DS011466-5
FIGURE 2. LMC6064 Noninverting Gain of 10 Amplifier,
Compensated to Handle Capacitive Loads
DS011466-6
FIGURE 3. Compensating for Large Capacitive Loads
with a Pull Up Resistor
DS011466-7
FIGURE 4. Example of Guard Ring in P.C. Board
Layout
www.national.com 8
Applications Hints (Continued)
The designer should be aware that when it is inappropriate
to lay out a PC board for the sake of just a few circuits, there
is another technique which is even better than a guard ring
on a PC board: Don’t insert the amplifier’s input pin into the
board at all, but bend it up in the air and use only air as an insulator. Air is an excellent insulator. In this case you may
have to forego some of the advantages of PC board construction, but the advantages are sometimes well worth the
effort of using point-to-point up-in-the-air wiring. See
Figure
6
.
Latchup
CMOS devices tend to be susceptible to latchup due to their
internal parasitic SCR effects.The (I/O) input and output pins
look similar to the gate of the SCR. There is a minimum current required to trigger the SCR gate lead. The LMC6064
and LMC6082 are designed to withstand 100 mA surge current on the I/O pins. Some resistive method should be used
to isolate any capacitance from supplying excess current to
the I/O pins. In addition, like an SCR, there is a minimum
holding current for any latchup mode. Limiting current to the
supply pins will also inhibit latchup susceptibility.
Typical Single-Supply
Applications
(V
+
=
5.0 V
DC
)
The extremely high input impedance, and low power consumption, of the LMC6064 make it ideal for applications that
require battery-powered instrumentation amplifiers. Examples of these types of applications are hand-held pH
probes, analytic medical instruments, magnetic field detectors, gas detectors, and silicon based pressure transducers.
Figure 7
shows an instrumentation amplifier that features
high differential and common mode input resistance
(
>
1014Ω), 0.01%gain accuracy at A
V
=
100, excellent
CMRR with 1 kΩ imbalance in bridge source resistance. Input current is less than 100 fA and offset drift is less than
2.5 µV/˚C. R
2
provides a simple means of adjusting gain
over a wide range without degrading CMRR. R
7
is an initial
trim used to maximize CMRR without using super precision
matched resistors. For good CMRR over temperature, low
drift resistors should be used.
DS011466-8
Inverting Amplifier
DS011466-9
Non-Inverting Amplifier
DS011466-10
Follower
FIGURE 5. Typical Connections of Guard Rings
DS011466-11
(Input pins are lifted out of PC board and soldered directly to components.
All other pins connected to PC board).
FIGURE 6. Air Wiring
www.national.com9
Typical Single-Supply
Applications
(Continued)
DS011466-12
If R
1
=
R
5,R3
=
R
6
, and R
4
=
R
7
; then
∴
AV≈ 100 for circuit shown (R
2
=
9.822k).
FIGURE 7. Instrumentation Amplifier
DS011466-13
FIGURE 8. Low-Leakage Sample and Hold
DS011466-14
FIGURE 9. 1 Hz Square Wave Oscillator
www.national.com 10
Physical Dimensions inches (millimeters) unless otherwise noted
14-Pin Ceramic Dual-In-Line Package
Order Number LMC6064AMJ/883
NS Package Number J14A
14-Pin Small Outline Package
Order Number LMC6064AIM or LMC6064IM
NS Package Number M14A
www.national.com11
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
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NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component is any component of a life 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.
National Semiconductor
Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
Email: support@nsc.com
www.national.com
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Tel: 81-3-5639-7560
Fax: 81-3-5639-7507
14-Pin Molded Dual-In-Line Package
Order Number LMC6064AMN, LMC6064AIN or LMC6064IN
NS Package Number N14A
LMC6064 Precision CMOS Quad Micropower Operational Amplifier
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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