High Accuracy
Instrumentation Amplifier
AMP02
FEATURES
Low Offset Voltage: 100 V max
Low Drift: 2 V/ⴗC max
Wide Gain Range: 1 to 10,000
High Common-Mode Rejection: 115 dB min
High Bandwidth (G = 1000): 200 kHz typ
Gain Equation Accuracy: 0.5% max
Single Resistor Gain Set
Input Overvoltage Protection
Low Cost
Available in Die Form
APPLICATIONS
Differential Amplifier
Strain Gage Amplifier
Thermocouple Amplifier
RTD Amplifier
Programmable Gain Instrumentation Amplifier
Medical Instrumentation
Data Acquisition Systems
FUNCTIONAL BLOCK DIAGRAM
8-Lead PDIP and CERDIP
16-Lead SOIC
RG1 1
8
RG2
–IN 2
7
V+
+IN 3
6
OUT
NC 3
14 NC
V– 4
5
REFERENCE
–IN 4
13 V+
+IN 5
12 SENSE
16 NC
NC 1
RG1 2
15 RG2
NC 6
11 OUT
V– 7
10 REFERENCE
NC 8
9 NC
NC = NO CONNECT
V+
+IN
RG
–IN
G=
3
–
1
RG1
8
RG2
2 +
7
6
OUT
5
4
REFERENCE
V–
VOUT
50k⍀
=
(+IN) – (–IN)
RG
(
)
+1
FOR SOL CONNECT SENSE TO OUTPUT
Figure 1. Basic Circuit Connections
GENERAL DESCRIPTION
The AMP02 is the first precision instrumentation amplifier
available in an 8-lead package. Gain of the AMP02 is set by a
single external resistor and can range from 1 to 10,000. No
gain set resistor is required for unity gain. The AMP02 includes
an input protection network that allows the inputs to be taken
60 V beyond either supply rail without damaging the device.
Laser trimming reduces the input offset voltage to under 100 µV.
Output offset voltage is below 4 mV, and gain accuracy is better
than 0.5% for a gain of 1000. ADI’s proprietary thin-film resistor process keeps the gain temperature coefficient under 50 ppm/°C.
Due to the AMP02’s design, its bandwidth remains very high
over a wide range of gain. Slew rate is over 4 V/µs, making the
AMP02 ideal for fast data acquisition systems.
A reference pin is provided to allow the output to be referenced
to an external dc level. This pin may be used for offset correction or level shifting as required. In the 8-lead package, sense is
internally connected to the output.
For an instrumentation amplifier with the highest precision,
consult the AMP01 data sheet.
REV. E
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2002. All rights reserved.
AMP02–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
Parameter
OFFSET VOLTAGE
Input Offset Voltage
Input Offset Voltage Drift
Output Offset Voltage
(@ VS = ⴞ15 V, VCM = 0 V, TA = 25ⴗC, unless otherwise noted.)
Symbol
Conditions
VIOS
TA = 25°C
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +85°C
TA = 25°C
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +85°C
VS = ± 4.8 V to ± 18 V
G = 100, 1000
G = 10
G=1
VS = ± 4.8 V to ± 18 V
–40°C ≤ TA ≤ +85°C
G = 1000, 100
G = 10
G=1
TCVIOS
VOOS
Output Offset Voltage Drift TCVOOS
Power Supply Rejection
PSR
Min
AMP02E
Typ
Max
20
50
0.5
1
4
50
100
200
2
4
10
100
120
110
90
105
90
70
110
95
75
dB
dB
dB
Differential, G ≤ 1000
Common Mode, G = 1000
TA = 25°C1
VCM = ± 11 V
G = 1000, 100
G = 10
G=1
VCM = ± 11 V
–40°C ≤ TA ≤ +85°C
G = 100, 1000
G = 10
G=1
10
16.5
OUTPUT RATING
Output Voltage Swing
GTC
NOISE
Voltage Density, RTI
fO = 1 kHz
G = 1000
G = 100
G = 10
G=1
fO = 1 kHz, G = 1000
0.1 Hz to 10 Hz
G = 1000
G = 100
G = 10
Noise Current Density, RTI in
Input Noise Voltage
en p-p
DYNAMIC RESPONSE
Small-Signal Bandwidth
(–3 dB)
G = 100, 1000
Slew Rate
Settling Time
BW
G=1
G = 10
SR
tS
G = 10, RL = 1 kΩ
To 0.01% ± 10 V Step
G = 1 to 1000
5
± 11
20
10
nA
pA/°C
nA
pA/°C
10
16.5
GΩ
GΩ
V
110
95
75
115
110
90
dB
dB
dB
110
95
75
120
110
90
105
90
70
115
105
85
dB
dB
dB
0.50
0.30
0.25
0.02
10k
0.006
20
en
4
250
2
15
120
115
95
1
TA = 25°C, RL = 1 kΩ
RL = 1 kΩ, –40°C ≤ TA ≤ +85°C
Output-to-Ground Short
Output-to-Ground Short
10
115
100
80
G = 1 to 1000
1 ≤ G ≤ 10002, 3
VOUT
Positive Current Limit
Negative Current Limit
± 11
G = 1000
G = 100
G = 10
G=1
G
µV
µV
µV/°C
mV
mV
µV/°C
110
95
75
RIN
Gain Range
Nonlinearity
Temperature Coefficient
200
350
4
8
20
200
dB
dB
dB
INPUT
Input Resistance
50 kΩ
+1
RG
40
100
1
2
9
100
115
100
80
2
150
1.2
9
G=
Unit
110
95
75
TA = 25°C
–40°C ≤ TA ≤ +85°C
TA = 25°C
–40°C ≤ TA ≤ +85°C
GAIN
Gain Equation
Accuracy
Max
125
110
90
IB
TCIB
IOS
TCIOS
IVR
CMR
AMP02F
Typ
115
100
80
INPUT CURRENT
Input Bias Current
Input Bias Current Drift
Input Offset Current
Input Offset Current Drift
Input Voltage Range
Common-Mode Rejection
Min
± 12
± 11
4
± 13
± 12
22
32
0.70
0.50
0.40
0.05
10k
1
0.006
20
50
± 12
± 11
50
%
%
%
%
V/V
%
ppm/°C
±13
±12
22
32
V
V
mA
mA
9
10
18
120
0.4
9
10
18
120
0.4
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
pA/√Hz
0.4
0.5
1.2
0.4
0.5
1.2
µV p-p
µV p-p
µV p-p
1200
300
200
6
1200
300
200
6
kHz
kHz
kHz
V/µs
10
10
µs
4
SENSE INPUT
Input Resistance
Voltage Range
RIN
25
± 11
25
± 11
kΩ
V
REFERENCE INPUT
Input Resistance
Voltage Range
Gain to Output
RIN
50
± 11
1
50
± 11
1
kΩ
V
V/V
–2–
REV. E
AMP02
Parameter
Symbol
POWER SUPPLY
Supply Voltage Range
Supply Current
VS
ISY
Conditions
Min
AMP02E
Typ
Max
Min
± 18
6
6
± 4.5
5
5
± 4.5
TA = 25°C
–40°C ≤ TA ≤ +85°C
AMP02F
Typ
5
5
Max
Unit
± 18
6
6
V
mA
mA
NOTES
1
Input voltage range guaranteed by common-mode rejection test.
2
Guaranteed by design.
3
Gain tempco does not include the effects of external component drift.
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS 1, 2
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational sections
of this specifications is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2
Absolute maximum ratings apply to both DICE and packaged parts, unless
otherwise noted.
3
θJA is specified for worst case mounting conditions, i.e., θJA is specified for
device in socket for P-DIP package; θJA is specified for device soldered to
printed circuit board for SOIC package.
Supply Voltage
± 18 V
Common-Mode Input Voltage [(V–) – 60 V] to [(V+) + 60 V]
Differential Input Voltage
[(V–) – 60 V] to [(V+) + 60 V]
Output Short-Circuit Duration
Continuous
Operating Temperature Range
–40°C to +85°C
Storage Temperature Range
–65°C to +150°C
Function Temperature Range
–65°C to +150°C
Lead Temperature (Soldering, 10 sec)
300°C
Package Type
JA3
JC
Unit
8-Lead Plastic DIP (P)
16-Lead SOIC (S)
96
92
37
27
°C/W
°C/W
ORDERING GUIDE
Model
AMP02EP
AMP02FP
AMP02AZ/883C
AMP02FS
AMP02GBC
AMP02FS-REEL
VIOS max @ VOOS max @ Temperature
TA = 25ⴗC
TA = 25ⴗC
Range
Package
Description
100 µV
200 µV
200 µV
200 µV
4 mV
8 mV
10 mV
8 mV
–40°C to +85°C
–40°C to +85°C
–55°C to +125°C
–40°C to +85°C
200 µV
8 mV
–40°C to +85°C
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead CERDIP
16-Lead SOIC
Die
16-Lead SOIC
V+
25k⍀
SENSE
25k⍀
OUT
25k⍀
25k⍀
REFERENCE
–IN
+IN
RG1 RG2
V–
Figure 2. Simplified Schematic
REV. E
–3–
AMP02
8
1. RG1
2. –IN
3. +IN
4. V–
5. REFERENCE
6. OUT
7. V+
8. RG2
9. SENSE
CONNECT SUBSTRATE TO V–
1
DIE SIZE 0.103 inch ⴛ 0.116 inch, 11,948 sq. mils
(2.62 mm ⴛ 2.95 mm, 7.73 sq. mm)
NOTE: PINS 1 and 8 are KELVIN CONNECTED
Die Characteristics
WAFER TEST LIMITS* (@ V = ⴞ15 V, V
S
CM
= 0 V, TA = 25ⴗC, unless otherwise noted.)
AMP02 GBC
Limits
Unit
VIOS
200
µV max
VOOS
8
mV max
Parameter
Symbol
Input Offset Voltage
Output Offset Voltage
Conditions
VS = ± 4.8 V to ± 18 V
G = 1000
G = 100
G = 10
G=1
110
110
95
75
Power Supply
Rejection
PSR
Input Bias Current
IB
20
nA max
Input Offset Current
IOS
10
nA max
Input Voltage Range
IVR
Guaranteed by CMR Tests
± 11
V min
CMR
VCM = ± 11 V
G = 1000
G = 100
G = 10
G=1
110
110
95
75
Common-Mode
Rejection
G=
Gain Equation Accuracy
Output Voltage Swing
VOUT
Supply Current
ISY
50 kΩ
+ 1, G = 1000
RG
RL = 1 kΩ
dB
dB
0.7
% max
± 12
V min
6
mA max
*Electrical tests are performed at wafer probe to the limits shown. Due to variations in assembly methods and normal yield loss, yield after packaging is not
guaranteed for standard product dice. Consult factory to negotiate specifications based on dice lot qualifications through sample lot assembly and testing.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although the
AMP02 features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
to avoid performance degradation or loss of functionality.
–4–
REV. E
Typical Performance Characteristics–AMP02
TA = 25ⴗC
1000 VS = ⴞ15V
160
3000 UNITS
FROM 3 RUNS
400 UNITS
FROM 3 RUNS
VS = ⴞ15V
140
800
NUMBER OF UNITS
700
600
500
400
300
120
100
80
60
40
200
0
–100 –80 –60 –40 –30 0 20 40 60 80 100
INPUT OFFSET VOLTAGE – V
0
TPC 1. Typical Distribution of
Input Offset Voltage
1100
TA = 25ⴗC
1000 VS = ⴞ15V
3000 UNITS
FROM 3 RUNS
0
NUMBER OF UNITS
NUMBER OF UNITS
700
600
500
400
300
–5
150
125
100
75
0
5
TPC 4. Typical Distribution of
Output Offset Voltage
20
40
32
VS = ⴞ15V
VCM = 0V
INPUT BIAS CURRENT – nA
2.0
1.5
1.0
0.5
25
0
50
TEMPERATURE – ⴗC
75
TPC 7. Input Offset Current
vs. Temperature
100
–1.0
6
24
20
16
12
8
0
–50
0
ⴞ5
ⴞ10
ⴞ15
POWER SUPPLY VOLTAGE – V
ⴞ20
TPC 6. Output Offset Voltage
Change vs. Supply Voltage
VS = ⴞ15V
VCM = 0V
5
4
3
2
1
4
–25
–0.5
VS = ⴞ15V
VCM = 0V
28
2.5
0
60
80 100 120 140 160
TCVOOS – V/ⴗC
TPC 5. Typical Distribution
of TCVOOS
TA = 25ⴗC
0.5
–1.5
0
ⴞ20
1.0
INPUT BIAS CURRENT – nA
3.0
ⴞ5
ⴞ10
ⴞ15
POWER SUPPLY VOLTAGE – V
1.5
400 UNITS
FROM 3 RUNS
VS = ⴞ15V
25
0
1
2
3
4
–5 –4 –3 –2 –1 0
OUTPUT OFFSET VOLTAGE – mV
0
200
50
100
INPUT OFFSET CURRENT – nA
0
TPC 3. Input Offset Voltage
Change vs. Supply Voltage
200
REV. E
5
TPC 2. Typical Distribution
of TCVIOS
900
0
–50
10
–10
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
TCVIOS – V/ⴗC
175
800
TA = 25ⴗC
15
20
100
INPUT OFFSET VOLTAGE – mV
NUMBER OF UNITS
900
20
INPUT OFFSET VOLTAGE – V
1100
–25
0
50
25
TEMPERATURE – ⴗC
75
TPC 8. Input Bias Current
vs. Temperature
–5–
100
0
0
ⴞ10
ⴞ15
ⴞ5
POWER SUPPLY VOLTAGE – V
TPC 9. Input Bias Current
vs. Supply Voltage
ⴞ20
AMP02
G = 100
40
G = 10
20
G=1
0
–20
–40
1k
10k
100k
1M
FREQUENCY – Hz
10M
TPC 10. Closed-Loop Voltage
Gain vs. Frequency
G = 1000
120
G = 100
100
G = 10
80
60
G=1
40
TA = 25ⴗC
20 VS = ⴞ15V
VCM = 2V p-p
0
1
100
1k
10
FREQUENCY – Hz
POWER SUPPLY REJECTION – dB
G = 10
100
G=1
80
60
40
TA = 25ⴗC
VS = ⴞ15V
⌬VS = ⴞ1V
20
1
10
1k
100
FREQUENCY – Hz
10k
100k
TPC 13. Positive PSR vs. Frequency
G=1
80
60
40
TA = 25ⴗC
VS = ⴞ15V
⌬VS = ⴞ1V
20
1
1k
VOLTAGE NOISE – nV/ Hz
50
40
30
20
10
1k
100
FREQUENCY – Hz
10k
100k
1
10
1k
100
FREQUENCY – Hz
10k
TPC 16. Voltage Noise Density
vs. Frequency
100k
100
10
1
80
1
100
10
VOLTAGE GAIN – G
1k
TA = 25ⴗC
VS = ⴞ15V
RL = 600⍀
VOUT = 20V p-p
0.100
G = 100
0.010
G=1
G = 10
1k
100
FREQUENCY – Hz
10k
TPC 15. Total Harmonic Distortion
vs. Frequency
100mV
10
0
90
0.01
10
TA = 25ⴗC
VS = ⴞ15V
f = 1kHz
TA = 25ⴗC
VS = ⴞ15V
G = 1000
60
G = 100
G = 10
100
TPC 14. Negative PSR vs. Frequency
70
VOLTAGE NOISE DENSITY – nV/ Hz
120
0
100
1s
NOISE VOLTAGE – 200nV/DIV
POWER SUPPLY REJECTION – dB
120
110
1.000
G = 1000
G = 100
120
TPC 12. Common-Mode Rejection
vs. Voltage Gain
140
G = 1000
TA = 25ⴗC
VS = ⴞ15V
130
70
100k
TPC 11. Common-Mode Rejection
vs. Frequency
140
0
10k
TOTAL HARMONIC DISTORTION – %
VOLTAGE GAIN – dB
60
COMMON-MODE REJECTION – dB
G = 1000
140
140
TA = 25ⴗC
VS = ⴞ15V
COMMON-MODE REJECTION – dB
80
1
100
10
VOLTAGE GAIN – G
TPC 17. RTI Voltage Noise
Density vs. Gain
–6–
1k
TIME – S
TPC 18. 0.1 Hz to 10 Hz Noise
AV = 1000
REV. E
AMP02
20
15
10
14
5
TA = 25ⴗC
VS = ⴞ15V
100 I
OUT = 20mA p-p
12
10
8
6
4
1k
10k
100k
FREQUENCY – Hz
0
10
1M
7
7
SLEW RATE – Vs
8
6
TA = –25ⴗC, +25ⴗC, +85ⴗC
5
1k
10k
100
LOAD RESISTANCE – ⍀
100k
TPC 20. Maximum Output Voltage
vs. Load Resistance
8
4
3
VS = ⴞ15V
TA = –40ⴗC, +25ⴗC, +85ⴗC
6
5
4
3
2
0
ⴞ10
ⴞ5
ⴞ15
SUPPLY VOLTAGE – V
TPC 22. Supply Current
vs. Supply Voltage
REV. E
ⴞ20
1
80
60
40
20
0
2
TPC 19. Maximum Output Swing
vs. Frequency
1
120
TA = 25ⴗC
VS = ⴞ15V
OUTPUT IMPEDANCE – ⍀
25
0
100
SUPPLY CURRENT – mA
16
TA = 25ⴗC
VS = ⴞ15V
RL = 1k⍀
OUTPUT VOLTAGE – V
PEAK- TO-PEAK AMPLITUDE – V
30
1
100
10
VOLTAGE GAIN – G
TPC 23. Slew Rate vs.
Voltage Gain
–7–
1k
–20
100
1k
100k
10k
FREQUENCY – Hz
1M
TPC 21. Closed Loop Output
Impedance vs. Frequency
10M
AMP02
The voltage gain can range from 1 to 10,000. A gain set resistor is
not required for unity-gain applications. Metal-film or wirewound
resistors are recommended for best results.
APPLICATIONS INFORMATION
Input and Output Offset Voltages
Instrumentation amplifiers have independent offset voltages
associated with the input and output stages. The input offset
component is directly multiplied by the amplifier gain, whereas
output offset is independent of gain. Therefore at low gain,
output-offset errors dominate while at high gain, input-offset
errors dominate. Overall offset voltage, VOS, referred to the
output (RTO) is calculated as follows:
The total gain accuracy of the AMP02 is determined by the
tolerance of the external gain set resistor, RG, combined with the
gain equation accuracy of the AMP02. Total gain drift combines
the mismatch of the external gain set resistor drift with that of the
internal resistors (20 ppm/°C typ). Maximum gain drift of the
AMP02 independent of the external gain set resistor is 50 ppm/°C.
VOS ( RTO ) = (VIOS × G ) + VOOS
All instrumentation amplifiers require attention to layout so
thermocouple effects are minimized. Thermocouples formed
between copper and dissimilar metals can easily destroy the
TCVOS performance of the AMP02, which is typically 0.5 µV/°C.
Resistors themselves can generate thermoelectric EMFs when
mounted parallel to a thermal gradient.
where VIOS and VOOS are the input and output offset voltage
specifications and G is the amplifier gain.
The overall offset voltage drift TCVOS, referred to the output, is
a combination of input and output drift specifications. Input
offset voltage drift is multiplied by the amplifier gain, G, and
summed with the output offset drift:
The AMP02 uses the triple op amp instrumentation amplifier
configuration with the input stage consisting of two transimpedance amplifiers followed by a unity-gain differential amplifier.
The input stage and output buffer are laser-trimmed to increase
gain accuracy. The AMP02 maintains wide bandwidth at all
gains as shown in Figure 3. For voltage gains greater than 10,
the bandwidth is over 200 kHz. At unity gain, the bandwidth of
the AMP02 exceeds 1 MHz.
TCVOS ( RTO ) = (TCVIOS × G ) + TCVOOS
where TCVIOS is the input offset voltage drift, and TCVOOS is
the output offset voltage drift. Frequently, the amplifier drift is
referred back to the input (RTI), which is then equivalent to an
input signal change:
TCVOS ( RTI ) = TCVIOS +
TCVOOS
G
80
For example, the maximum input-referred drift of an
AMP02EP set to G = 1000 becomes:
VOLTAGE GAIN – dB
TCVOS ( RTI ) = 2 µV oC +
60
100 µV oC
= 2.1 µV oC
1000
Input Bias and Offset Currents
Input transistor bias currents are additional error sources that
can degrade the input signal. Bias currents flowing through the
signal source resistance appear as an additional offset voltage.
Equal source resistance on both inputs of an IA will minimize
offset changes due to bias current variations with signal voltage
and temperature; however, the difference between the two bias
currents (the input offset current) produces an error. The magnitude of the error is the offset current times the source resistance.
0
G = 100
G = 10
G=1
–40
1k
10k
100k
FREQUENCY – Hz
1M
10M
Figure 3. The AMP02 Keeps Its Bandwidth at
High Gains
Common-Mode Rejection
Ideally, an instrumentation amplifier responds only to the difference between the two input signals and rejects common-mode
voltages and noise. In practice, there is a small change in output
voltage when both inputs experience the same common-mode
voltage change; the ratio of these voltages is called the
common-mode gain. Common-mode rejection (CMR) is the
logarithm of the ratio of differential-mode gain to common-mode
gain, expressed in dB. Laser trimming is used to achieve the
high CMR of the AMP02.
Gain
The AMP02 only requires a single external resistor to set the
voltage gain. The voltage gain, G, is:
50 kΩ
+1
RG
and
RG =
20
G = 1000
–20
A current path must always be provided between the differential
inputs and analog ground to ensure correct amplifier operation.
Floating inputs such as thermocouples should be grounded
close to the signal source for best common-mode rejection.
G=
40
TA = 25ⴗC
VS = ⴞ15V
50 kΩ
G –1
–8–
REV. E
AMP02
3
+IN
8
RG2
V1 25k⍀
25k⍀
R
25k⍀
RG
RG1
1
SENSE
(SOIC-16 ONLY)
6
OUT
R
25k⍀
25k⍀
–IN
2
25k⍀
5
REFERENCE
V2
Figure 4. Triple Op Amp Topology
Figure 4 shows the triple op amp configuration of the AMP02.
With all instrumentation amplifiers of this type, it is critical not
to exceed the dynamic range of the input amplifiers. The amplified differential input signal and the input common-mode voltage must not force the amplifier’s output voltage beyond ± 12 V
(VS = ± 15 V) or nonlinear operation will result.
Grounding
The majority of instruments and data acquisition systems have
separate grounds for analog and digital signals. Analog ground may
also be divided into two or more grounds that will be tied together
at one point, usually at the analog power supply ground. In
addition, the digital and analog grounds may be joined—normally
at the analog ground pin on the A/D converter. Following this
basic practice is essential for good circuit performance.
The input stage amplifier’s output voltages at V1 and V2 equal:
2R VD
V1 = – 1 +
+ VCM
RG 2
= –G
Mixing grounds causes interactions between digital circuits and the
analog signals. Since the ground returns have finite resistance
and inductance, hundreds of millivolts can be developed between
the system ground and the data acquisition components. Using
separate ground returns minimizes the current flow in the sensitive
analog return path to the system ground point. Consequently, noisy
ground currents from logic gates interact with the analog signals.
VD
+ VCM
2
2R VD
V2 = 1 +
+ VCM
RG 2
=G
Inevitably, two or more circuits will be joined together with
their grounds at differential potentials. In these situations, the
differential input of an instrumentation amplifier, with its high
CMR, can accurately transfer analog information from one
circuit to another.
VD
+ VCM
2
Sense and Reference Terminals
where:
VD
The sense terminal completes the feedback path for the instrumentation amplifier output stage and is internally connected directly
to the output. For SOIC devices, connect the sense terminal to
the output. The output signal is specified with respect to the reference terminal, which is normally connected to analog ground.
The reference may also be used for offset correction level shifting. A reference source resistance will reduce the common-mode
rejection by the ratio of 25 kΩ/RREF. If the reference source resistance is 1 Ω, the CMR will be reduced 88 dB (25 kΩ/1 Ω = 88 dB).
= Differential input voltage
= (+IN) – (–IN)
VCM = Common-mode input voltage
G
= Gain of instrumentation amplifier
If V1 and V2 can equal ± 12 V maximum, the common-mode
input voltage range is:
GVD
CMVR = ± 12 V −
2
REV. E
–9–
AMP02
Overvoltage Protection
Power Supply Considerations
Instrumentation amplifiers invariably sit at the front end of
instrumentation systems where there is a high probability of
exposure to overloads. Voltage transients, failure of a transducer,
or removal of the amplifier power supply while the signal source is
connected may destroy or degrade the performance of an unprotected device. A common technique is to place limiting resistors in
series with each input, but this adds noise. The AMP02 includes
internal protection circuitry that limits the input current to ±4 mA
for a 60 V differential overload (see Figure 5) with power off,
± 2.5 mA with power on.
Achieving the rated performance of precision amplifiers in a
practical circuit requires careful attention to external influences.
For example, supply noise and changes in the nominal voltage
directly affect the input offset voltage. A PSR of 80 dB means
that a change of 100 mV on the supply (not an uncommon
value) will produce a 10 µV input offset change. Consequently,
care should be taken in choosing a power unit that has a low
output noise level, good line and load regulation, and good
temperature stability. In addition, each power supply should be
properly bypassed.
4
LEAKAGE CURRENT – mA
3
TA = 25ⴗC
VS = ⴞ15V
POWER OFF
2
POWER ON
1
0
–1
–2
–3
–4
–100
–80
–60
–40
–20
0
20
40
60
80
100
DIFFERENTIAL INPUT VOLTAGE
Figure 5. AMP02’s Input Protection Circuitry Limits Input
Current During Overvoltage Conditions
–10–
REV. E
AMP02
OUTLINE DIMENSIONS
8-Lead Plastic Dual-in-Line Package [PDIP]
(N-8)
8-Lead Ceramic DIP - Glass Hermetic Seal [CERDIP]
(Q-8)
Dimensions shown in inches and (millimeters)
Dimensions shown in inches and (millimeters)
0.005 (0.13)
MIN
0.375 (9.53)
0.365 (9.27)
0.355 (9.02)
8
5
1
4
8
0.295 (7.49)
0.285 (7.24)
0.275 (6.98)
0.150 (3.81)
0.130 (3.30)
0.110 (2.79)
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
5
0.310 (7.87)
0.220 (5.59)
PIN 1
1
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.100 (2.54)
BSC
0.180
(4.57)
MAX
0.055 (1.40)
MAX
4
0.100 (2.54) BSC
0.150 (3.81)
0.135 (3.43)
0.120 (3.05)
0.015
(0.38)
MIN
0.200 (5.08)
MAX
0.150 (3.81)
MIN
0.200 (5.08)
0.125 (3.18)
0.015 (0.38)
0.010 (0.25)
0.008 (0.20)
SEATING
PLANE
0.060 (1.52)
0.050 (1.27)
0.045 (1.14)
0.060 (1.52)
0.015 (0.38)
0.023 (0.58)
0.014 (0.36)
SEATING
0.070 (1.78) PLANE
0.030 (0.76)
15
0
0.015 (0.38)
0.008 (0.20)
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETERS DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
COMPLIANT TO JEDEC STANDARDS MO-095AA
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
16-Lead Standard Small Outline Package [SOIC]
Wide Body
(R-16)
Dimensions shown in millimeters and (inches)
10.50 (0.4134)
10.10 (0.3976)
9
16
7.60 (0.2992)
7.40 (0.2913)
1.27 (0.0500)
BSC
0.30 (0.0118)
0.10 (0.0039)
COPLANARITY
0.10
10.65 (0.4193)
10.00 (0.3937)
8
1
0.51 (0.0201)
0.33 (0.0130)
0.75 (0.0295)
ⴛ 45ⴗ
0.25 (0.0098)
2.65 (0.1043)
2.35 (0.0925)
SEATING
PLANE
0.32 (0.0126)
0.23 (0.0091)
8ⴗ
0ⴗ
1.27 (0.0500)
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-013AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
REV. E
0.320 (8.13)
0.290 (7.37)
0.405 (10.29) MAX
–11–
AMP02
Revision History
Location
Page
1/03—Data Sheet changed from REV. D to REV. E.
Edits to Die Characteristics .............................................................................................................................................................4
PRINTED IN U.S.A.
Updated OUTLINE DIMENSIONS.............................................................................................................................................11
C00248–0–1/03(E)
Edits to Figure 2 .............................................................................................................................................................................3
–12–
REV. E
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